CN116761690A

CN116761690A - Superalloy powder mixture for liquid-assisted additive manufacturing of superalloy components

Info

Publication number: CN116761690A
Application number: CN202280009904.3A
Authority: CN
Inventors: K·奥兹拜萨尔; A·卡梅尔
Original assignee: Siemens Energy Inc
Current assignee: Siemens Energy Inc
Priority date: 2021-01-19
Filing date: 2022-01-18
Publication date: 2023-09-15

Abstract

A superalloy powder mixture is provided for additive manufacturing or welding of a metal component or portion thereof. The superalloy powder mixture comprises at least 51% by weight of a high melting superalloy powder and at least 5% by weight of a low melting superalloy powder. The solidus temperature of the low melting point superalloy powder may be 50 ℃ to 220 ℃ lower than the solidus temperature of the high melting point superalloy powder. Each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture may have a nickel content of greater than 40% by weight, and may have an aluminum content of greater than 1.5% by weight. The low melting point superalloy powder may comprise at least 5% tantalum by weight and the high melting point superalloy powder may comprise less than half of its tantalum content by weight as compared to the tantalum content by weight in the low melting point superalloy powder.

Description

Superalloy powder mixture for liquid-assisted additive manufacturing of superalloy components

Background

The present invention relates generally to the field of additive manufacturing and welding, and more particularly to additive manufacturing and/or welding of components made of difficult-to-weld superalloys for use in gas turbines and other high temperature applications.

Nickel-base superalloys are metal alloys that can be used to form gamma '(gamma') precipitation-strengthened metal parts that advantageously combine mechanical strength, thermal fatigue resistance, oxidation resistance, type I or type II corrosion resistance, and thermal creep deformation resistance. High gamma prime formed nickel-based superalloys are commonly used for high temperature applications (e.g., above 950 ℃). For example, parts cast from such superalloys may include blades, guide vanes, and other hot gas path components for gas turbine engines for aerospace, marine, and industrial applications. However, additive manufacturing and/or welding of high gamma prime shaped nickel-based superalloy materials is known to be difficult because such superalloys experience solidification and grain boundary liquefaction cracking problems during such processes. Furthermore, such additively manufactured or welded superalloy components are susceptible to strain age cracking during subsequent heat treatments. Accordingly, there is a need for improved processes for welding and/or additive manufacturing of components made of superalloys, particularly difficult to weld nickel-based superalloys, which reduce the amount, size and/or volume of voids and cracks and avoid the need to perform hot isostatic pressing operations to collapse such voids and cracks in order to produce parts that can be used in high temperature applications.

Disclosure of Invention

Various disclosed embodiments include systems and methods that may be used to facilitate additive manufacturing of components (or portions thereof) made of one or more superalloys. In an example, the elements that make up the difficult-to-weld superalloy are divided into at least two portions, referred to herein as a high-melting superalloy powder and a low-melting superalloy powder, such that additive manufacturing or welding using such superalloy powder mixtures produces fewer microcracks when the two portions are combined in a mixture in a predetermined ratio.

In one aspect, a superalloy powder mixture for additive manufacturing or welding of a metal component or portion thereof comprises at least 51% by weight of a high melting superalloy powder and at least 5% by weight of a low melting superalloy powder, wherein the low melting superalloy powder has a solidus temperature 50 ℃ to 220 ℃ lower than the solidus temperature of the high melting superalloy powder, wherein each of the high melting superalloy powder, the low melting superalloy powder, and the superalloy powder mixture has a nickel content of greater than 40% by weight and an aluminum content of greater than 1.5% by weight, wherein the low melting superalloy powder comprises at least 5% by weight tantalum, and wherein the high melting superalloy powder comprises less than half of its tantalum content by weight as compared to the tantalum content in the low melting superalloy powder by weight.

In another aspect, a method includes additive manufacturing at least a portion of a metal component using a superalloy powder mixture.

In another aspect, a method includes welding a metal component using a superalloy powder mixture.

In another aspect, an additive manufacturing method includes sequentially depositing and fusing layers of a superalloy powder mixture together to build up an additive portion, and heat treating the additive portion at a temperature of 1200 ℃ or above 1200 ℃ to form a homogenized base alloy contained in the additive portion, the base alloy having a chemical composition defined by the superalloy powder mixture.

In another aspect, an additive manufacturing method includes dispensing a combination of a binder and a superalloy powder mixture, and heat treating the component in a furnace to: the binder is burned off, the component is solid state sintered, the low melting point superalloy powder is melted to fill the internal pores of the component, and a base alloy contained in the component is formed via homogenization, the base alloy having a chemical composition defined by the superalloy powder mixture.

In another aspect, an additive manufacturing method includes: dispensing a first bond of the binder and the high melting point superalloy powder layer by layer to build up an additive portion comprising the first bond; dispensing a second combination of an adhesive and a low melting point superalloy powder to produce at least one sheet on at least one surface of the additive portion, the at least one sheet comprising one or more layers of the second combination; and heat treating the additive portion in a furnace to: burning out the binder in the additive portion; solid state sintering of the additive portion; melting the low melting point superalloy powder in the at least one sheet to fill the internal pores of the additive portion; forming, via homogenization, a base alloy contained in the additive portion, the base alloy having a chemical composition defined by a high-melting superalloy powder and a low-melting superalloy powder from the first binder and the second binder, wherein the low-melting superalloy powder has a solidus temperature 50 ℃ to 220 ℃ lower than the high-melting superalloy powder, wherein each of the high-melting superalloy powder, the low-melting superalloy powder, and the base alloy has a nickel content of greater than 40% by weight and an aluminum content of greater than 1.5% by weight, wherein the low-melting superalloy powder comprises at least 5% by weight tantalum, and wherein the high-melting superalloy powder comprises less than half of the tantalum content by weight as compared to the tantalum content by weight in the low-melting superalloy powder.

In another aspect, an extrudable filament for additive manufacturing comprises a superalloy powder mixture and a binder that binds the superalloy powder mixture together, wherein the binder comprises a polymer, and wherein the filament comprises greater than 50% by volume of the superalloy powder mixture and less than 50% by volume of the binder.

In another aspect, a welding wire includes a metallic tubular sheath that encapsulates a superalloy powder mixture, wherein the metallic sheath comprises nickel.

In another aspect, a wire for additive manufacturing or welding of a metal part or portion thereof comprises an elongated body, wherein the elongated body comprises therein a superalloy powder mixture comprising: at least 51% by weight of a high melting point superalloy powder; and at least 5% by weight of a low melting point superalloy powder. The solidus temperature of the low melting point superalloy powder is 50 ℃ to 220 ℃ lower than the solidus temperature of the high melting point superalloy powder. Each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture has an aluminum content of greater than 1.5% by weight, wherein the low melting point superalloy powder comprises at least 5% tantalum by weight. Also, the high melting point superalloy powder comprises less than half of its tantalum content by weight percent as compared to the tantalum content by weight percent in the low melting point superalloy powder.

In another aspect, the metal component includes at least a portion comprising a superalloy having a chemical composition corresponding to the superalloy powder mixture.

In another aspect, a turbine blade or turning vane includes at least a portion comprising a superalloy having a chemical composition corresponding to a superalloy powder mixture.

In another aspect, the pre-sintered preform includes at least a portion comprising a superalloy having a chemical composition corresponding to the superalloy powder mixture.

In another aspect, the high melting point superalloy comprises, by weight, 7.7% to 8.1% chromium, 10.6% to 11% cobalt, 4.5% to 6.5% aluminum, 10.6% to 11% tungsten, 0.3% to 0.55% molybdenum, 0.05% to 0.08% carbon, and greater than 40% nickel.

In another aspect, the low melting point superalloy comprises 9.5% to 10.5% chromium, 2.9% to 3.4% cobalt, 8.0% to 9.0% aluminum, 3.8% to 4.3% tungsten, 0.8% to 1.2% molybdenum, 10% to 20% tantalum, 3% to 12% hafnium, and greater than 40% nickel by weight.

In another aspect, the low melting point superalloy comprises 9.5% to 10.5% chromium, 2.9% to 3.4% cobalt, 7.0% to 9.0% aluminum, 3.8% to 4.3% tungsten, 0.8% to 1.2% molybdenum, 12% to 22% tantalum, and greater than 40% nickel by weight.

In some aspects, the low-melting superalloy and/or the high-melting superalloy may be in powder form, particularly powder particles having a powder particle size distribution between 10 microns and 100 microns.

In some aspects, the superalloy powder mixture may have a total aluminum content and optionally a titanium content of greater than 4% by weight.

In some aspects, the superalloy powder mixture may comprise, by weight, 4% to 23% chromium, 4% to 20% cobalt, 0% to 8% titanium, 1.5% to 8% aluminum, 0% to 11% tungsten, 0% to 4% molybdenum, 1% to 13% tantalum, 0% to 0.2% carbon, 0% to 1% zirconium, 0% to 4% hafnium, 0% to 4% rhenium, 0% to 0.1% yttrium and/or cerium, 0% to 0.04% boron, 0% to 2% niobium, 0% to 1.5% optional incidental elements and unavoidable impurities, and the balance nickel.

In some aspects, each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture may have an aluminum content of greater than 4.0% by weight.

In some aspects, the low melting point superalloy powder may comprise at least 10% tantalum by weight.

In some aspects, the low melting point superalloy powder may comprise at least 0.5% hafnium by weight, and the high melting point superalloy powder may comprise less than half of its hafnium content by weight as compared to the hafnium content by weight in the low melting point superalloy powder.

In some aspects, at least one of the amounts of chromium, aluminum, or molybdenum in the low melting point superalloy powder in weight percent may be at least 15% to 75% lower than the corresponding weight percent in the high melting point superalloy powder.

In some aspects, the amount of at least one of cobalt or tungsten in the high and low melting point superalloy powder may be at least 50% to 75% lower than the corresponding weight percentage in the low melting point superalloy powder.

In some aspects, the low melting point superalloy powder may have a liquidus temperature above 1300 ℃.

In some aspects, each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture may have a nickel content of greater than 45% by weight and an aluminum content of greater than 5.5% by weight.

In some aspects, the low melting point superalloy powder may comprise at least 8% aluminum by weight.

In some aspects, the low melting point superalloy powder may comprise at least 3% hafnium by weight.

In some aspects, the high melting point superalloy powder may comprise up to 4.5% tantalum, particularly up to 4.0% tantalum, further particularly less than 3.5% tantalum, further particularly less than 1.9% tantalum, further particularly up to 1.0% tantalum, further particularly up to 0.05% tantalum, further particularly 0% tantalum by weight.

In some aspects, the high melting point superalloy powder may comprise up to 0.05% hafnium by weight.

In some aspects, the low melting point superalloy powder may comprise a maximum of 3.4% cobalt by weight, particularly 2.9% to 3.4% cobalt.

In some aspects, the low melting point superalloy powder may comprise at least 3.8% tungsten by weight, particularly 3.8% to 4.3% tungsten.

In some aspects, the superalloy powder mixture may comprise at least 9% tungsten by weight.

In some aspects, the superalloy powder mixture may comprise up to 6.2% tantalum by weight.

In some aspects, the solidus temperature of the low melting superalloy powder may be 70 ℃ to 200 ℃, specifically 90 ℃ to 170 ℃, further specifically 100 ℃ to 160 ℃, further specifically 120 ℃ to 140 ℃, below the solidus temperature of the high melting superalloy powder.

In some aspects, the solidus temperature of the low melting superalloy powder may be 10 ℃ to 150 ℃, particularly 10 ℃ to 100 ℃, further particularly 10 ℃ to 50 ℃, further particularly 20 ℃ to 50 ℃, further particularly about 35 ℃ to 45 ℃, below the grain boundary melting temperature of the homogenized base alloy defined by the chemical composition of the superalloy powder.

In some aspects, the solidus temperature of the high melting point superalloy powder may be between 1330 ℃ and 1450 ℃, particularly between 1350 ℃ and 1430 ℃.

In some aspects, the solidus temperature of the low melting superalloy powder may be between 1200 ℃ and 1370 ℃, particularly between 1210 ℃ and 1360 ℃.

In some aspects, the superalloy powder mixture may comprise a maximum of 0.5% titanium, particularly a maximum of 0.05% titanium, and further particularly a maximum of 0.005% titanium by weight.

In some aspects, the superalloy powder mixture may have an aluminum content of at least 6% by weight.

In some aspects, the high melting point superalloy powder may comprise 4.5% to 6.5% aluminum by weight.

In some aspects, the low melting point superalloy powder may comprise at least 8% aluminum by weight, particularly 8% to 9% aluminum by weight.

In some aspects, the superalloy powder mixture may comprise up to 2.0% hafnium by weight.

In some aspects, the low melting point superalloy powder may comprise 10% to 20% tantalum and 3% to 12% hafnium by weight.

In some aspects, at least one of the low melting point superalloy powder or the high melting point superalloy powder may comprise from 0.03% to 0.07% by weight of yttrium and/or cerium.

In some aspects, the low melting point superalloy powder may comprise a maximum of 0.08% carbon by weight.

In some aspects, the high melting point superalloy powder may comprise 0% to 2% titanium, 0% to 1% tantalum, 0% to 1% zirconium, 0% to 0.05% hafnium, 0% to 0.05% rhenium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron by weight.

In some aspects, the low melting point superalloy powder may comprise 0% to 2% titanium, 0% to 0.08% carbon, 0% to 1% zirconium, 0% to 0.05% rhenium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron by weight.

In some aspects, the low melting point superalloy powder may comprise 0% to 2% titanium, 0% to 0.08% carbon, 0% to 1% zirconium, and 0% to 12% hafnium, 0% to 3.2% rhenium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron by weight.

In some aspects, the high melting point superalloy powder may comprise, by weight, 6% to 7.3% chromium, 11% to 13% cobalt, 5.5% to 6.5% aluminum, 4.7% to 5.2% tungsten, 1.2% to 2.2% molybdenum, and 2% to 4.2% rhenium.

In some aspects, the high melting point superalloy powder may comprise 0% to 0.05% titanium, 0% to 4.5% tantalum, 0% to 0.15% carbon, 0% to 1% zirconium, 0% to 1.7% hafnium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron by weight.

In some aspects, the low melting point superalloy powder may comprise at least 7% titanium by weight, and wherein the high melting point superalloy powder may comprise less than half of its titanium content by weight as compared to the titanium content by weight in the low melting point superalloy powder.

In some aspects, each of the superalloy powder mixture, the high melting superalloy powder, and the low melting superalloy powder may comprise from 0% to 0.01% by weight of one or more unavoidable impurities.

In some aspects, each of the superalloy powder mixture, the high melting point superalloy powder, and the low melting point superalloy powder may comprise from 0% to 1.5% by weight of one or more incidental elements other than chromium, cobalt, titanium, aluminum, tungsten, molybdenum, tantalum, carbon, zirconium, hafnium, rhenium, yttrium, cerium, and boron.

In some aspects, the superalloy powder mixture may comprise from 7.8% to 8.8% chromium by weight.

In some aspects, the superalloy powder mixture may comprise 11.7% to 15.5% chromium by weight.

In some aspects, the high melting point superalloy powder may comprise up to 0.05% titanium by weight, preferably 0.005% titanium.

In some aspects, the high melting point superalloy powder may comprise from 7.7% to 8.1% chromium by weight.

In some aspects, the high melting point superalloy powder may comprise 12% to 16% chromium by weight.

In some aspects, the low melting point superalloy powder may comprise up to 0.05% titanium by weight, preferably 0.005% titanium.

In some aspects, the weight ratio of high-melting superalloy powder to low-melting superalloy powder in the superalloy powder mixture may be between 95:05 and 51:49, particularly between 90:10 and 70:30, further particularly between 85:15 and 75:25, further particularly between 82:18 and 78:22, further particularly between 94:06 and 76:24.

In some aspects, at least 70% by weight of the additive portion may be formed from a high melting point superalloy powder and a low melting point superalloy powder, with the balance comprising at least one intermediate melting point superalloy powder that is nickel-based and has a solidus temperature between the solidus temperatures of the respective high melting point superalloy powder and low melting point superalloy powder.

In some aspects, at least 70%, particularly at least 90%, further particularly at least 95%, further particularly at least 99%, further particularly 100% by weight of the additive portion may be formed from a high melting point superalloy powder and a low melting point superalloy powder.

In some aspects, the low melting point superalloy powder may have a chemical composition that enables the low melting point superalloy powder to fill solidification cracks in each of the deposited layers prior to heat treating the additive portion so as to reduce solidification cracks in the deposited layers.

In some aspects, the low melting point superalloy powder may have a chemical composition that enables the low melting point superalloy powder to enable each deposited layer to exert less strain on Heat Affected Zone (HAZ) layer grain boundaries before any heat treatment of the additive portion in order to reduce grain boundary cracking.

In some aspects, the low melting point superalloy powder may have a chemical composition that enables the low melting point superalloy powder to solidify after solidification and strength of liquefied grain boundaries of a Heat Affected Zone (HAZ) prior to heat treating the additive portion in order to reduce HAZ liquefaction cracking.

In aspects that include a binder, the binder may include a polymer, and the bond may include greater than 50% by volume of the superalloy powder mixture and less than 50% of the binder.

In aspects that include an adhesive, the adhesive may include a thermoplastic and/or a wax.

In aspects including the second bond, the second bond may further comprise a high melting point superalloy powder.

In aspects including the second bond, the weight ratio of high-melting superalloy powder to low-melting superalloy powder in the sheet may be between 05:95 and 30:70, particularly between 10:90 and 25:75, further particularly between 18:82 and 22:78.

In aspects involving the method, the method may further include heating the metal component in a furnace to at least partially homogenize the portion formed from the superalloy powder mixture.

In aspects involving the method, the method may further comprise heating the metal part in the furnace at a temperature of 1200 ℃ or greater than 1200 ℃ for at least 120 minutes.

In aspects involving methods, an additive portion may be deposited on a substrate corresponding to an existing metal part having a chemical composition that does not correspond to a base alloy.

In aspects involving methods, the methods may further include brazing the additive portion to the metal part.

In aspects involving the method, such metal parts may comprise greater than 0.05% by weight titanium, and the base alloy may comprise a maximum of 0.05% by weight titanium.

In aspects involving methods, such metal components may include the root of a blade.

In aspects involving methods, the additive portion may form at least a portion of a turbine blade or turbine guide vane.

In aspects involving methods, the superalloy powder mixture may be deposited and fused together via a Selective Laser Melting (SLM) 3D printer to form the additive portion.

In aspects involving methods, a superalloy powder mixture may be deposited and fused together to form an additive portion via a Directional Energy Deposition (DED) nozzle that provides the superalloy powder mixture and emits an energy beam that melts the superalloy powder mixture.

In aspects involving methods, the superalloy powder mixture may be deposited and fused together via a Laser Wire Deposition (LWD) system that employs a welding wire to provide the superalloy powder mixture.

In aspects involving methods, during sequential deposition and fusion together of layers of superalloy powder mixture, the method may include filling cracks and/or preventing cracking of the deposited superalloy in order to reduce the overall length of cracks in the cross section of the additive portion to an average of less than 1.0mm/mm ² 。

In aspects involving methods, the superalloy powder mixture may have a composition that causes less microcracking of the superalloy powder mixture when the additive portion is cooled to room temperature prior to heat treating the additive portion, relative to alternatively implementing a method of stacking the additive portion using a powder comprising only the base alloy.

In aspects involving methods, the superalloy powder mixture may have a composition that causes less microcracking of the superalloy powder mixture when the additive portion is cooled to room temperature prior to heat treating the additive portion, relative to alternatively implementing a method of stacking the additive portion using only high melting superalloy powder that is not mixed with low melting superalloy powder.

In aspects involving methods, the superalloy powder mixture may have a composition that causes less microcracking of the superalloy powder mixture when the additive portion is cooled to room temperature prior to heat treating the additive portion, relative to alternatively implementing methods that stack the additive portion using only low melting superalloy powder that is not mixed with high melting superalloy powder.

In aspects involving methods, fewer microcracks may be achieved without subjecting the additive portion to a hot isostatic pressing operation.

In aspects involving the method, the gamma prime volume fraction of the base alloy may be greater than 30%, particularly greater than 50%, further particularly greater than 70%.

The foregoing has outlined rather broadly the features of the present invention so that those skilled in the art may better understand the detailed description that follows. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims. Those skilled in the art will appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures or steps for carrying out the same purposes of the present invention. Those skilled in the art will also realize that such equivalent constructions or steps do not depart from the spirit and scope of the invention in its broadest form.

Furthermore, before the following detailed description is started, it is to be understood that various definitions for certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. While certain terms may include a variety of embodiments, the appended claims may expressly limit these terms to particular embodiments.

Drawings

To facilitate identification of a discussion of any particular element or act, one or more of the most significant digits in a reference numeral refer to the reference numeral to which that element was first introduced.

FIG. 1 illustrates a functional block diagram of an exemplary system that facilitates additive manufacturing or welding of at least a portion of a superalloy component via an exemplary Liquid Assisted AM (LAAM) process.

Fig. 2 shows an image of a cross-section of a sample block manufactured from CM 247LC superalloy additive using a conventional additive manufacturing process.

Fig. 3 shows an image of a cross-section of a sample block additively manufactured via an exemplary LAAM process.

Fig. 4 shows an enlarged view of the image depicted in fig. 3.

Fig. 5 shows a graph plotting yield strength comparing a superalloy sample made of CM 247LC superalloy via LAAM, via HIP with a superalloy sample made of CM 247LC superalloy via casting.

Fig. 6 shows a graph plotting tensile strength comparing a superalloy sample made of CM 247LC superalloy via LAAM, via HIP with a superalloy sample made of CM 247LC superalloy via casting.

Fig. 7 shows a graph plotting elongation comparing a superalloy sample made of CM 247LC superalloy via LAAM, via HIP with a superalloy sample made of CM 247LC superalloy via casting.

Fig. 8 shows an image of a cross section of a sample block cast from CM 247 LC superalloy after oxidation testing.

Fig. 9 shows an image of a cross section of a sample block made via an exemplary LAAM process after an oxidation test.

Fig. 10 shows a schematic view of a possible theory on how the LAAM process generates fewer cracks during the additive manufacturing process compared to an AM process using conventional superalloy powders.

Fig. 11 shows a schematic view of an exemplary LAAM process implemented by an additive system corresponding to an SLM 3D printer.

Fig. 12 shows a perspective view of a turbine blade made of a conventional superalloy, which includes an upper tip portion having a number of cracks.

Fig. 13 shows a perspective view of the turbine blade depicted in fig. 12, which is refurbished to include a new upper tip portion created via an exemplary LAAM process.

Fig. 14 shows an image of a cross section of a sample block additively manufactured via an exemplary crack healing AM process.

FIG. 15 illustrates a welding wire that may be used in an LWD process to additively manufacture a component (or portion thereof) or join superalloy metal parts together.

Fig. 16 illustrates an adhesive-based micro-dispensing 3D printer process that dispenses an adhesive in combination with a superalloy powder mixture.

Fig. 17 illustrates another adhesive-based micro-dispensing 3D printer process that dispenses an adhesive in combination with a superalloy powder mixture.

Fig. 18 illustrates a method of facilitating additive manufacturing according to an exemplary LAAM process.

Fig. 19 illustrates another method of facilitating additive manufacturing according to an exemplary crack healing AM process.

Detailed Description

Various techniques related to systems, methods, and materials that facilitate additive manufacturing (and/or welding) of components made of superalloy materials will now be described with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout. Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

Exemplary embodiments of one or more of the inventions described herein relate to making a component comprising a nickel-based superalloy comprising greater than 40% nickel, the nickel-based superalloy being gamma prime precipitation strengthened by comprising greater than 4% by weight aluminum and/or titanium to achieve a gamma prime volume fraction of greater than 30%. Such superalloys are referred to herein as difficult-to-weld superalloys because their high gamma prime fraction contributes to the problems of solidification and grain boundary liquefaction cracking when welded or when used in an Additive Manufacturing (AM) process to produce or repair a metal component. Examples of commercially available difficult-to-weld superalloys for use in constructing gas turbine components (e.g., blades and guide vanes of a gas turbine) include: CM 247 LC, ren 142, ren 80 and Ren N5 brands or brands of superalloys. CM 247 LC is a trademark of Cannon-mussegon corporation, michigan, usa. Further examples of superalloys and processes for making them are set forth in U.S. patent No. 9,388,479B2, which is herein incorporated by reference in its entirety, issued at 2016, 7, 12.

The following example illustrates a new process, referred to herein as Liquid Assisted Additive Manufacturing (LAAM), that is capable of implementing an additive manufacturing process to manufacture and/or repair components made of difficult-to-weld superalloys. Referring to fig. 1, an exemplary additive system 100 for implementing the LAAM process is schematically illustrated. For AM processes, such an additive system 100 may correspond to a 3D printer, such as a Selective Laser Melting (SLM) 3D printer with a powder bed arrangement. However, as discussed in more detail below, the described additive system 100 may correspond to other types of 3D printers and/or welding systems.

In this example, the additive system may be configured to apply a thin layer 116 of the superalloy powder mixture 102 to a substrate 112 made of a superalloy or other metal. In some examples, the energy source 110 may be configured to selectively melt the layer (or a predetermined portion thereof). For example, the energy source 110 (e.g., a laser) may be operated to output one or more energy beams 108 (e.g., laser beams), the one or more energy beams 108 being aimed at predetermined locations to melt the superalloy powder mixture 102 on the substrate 112 along various predetermined tool paths. The melted superalloy mixture may cool and solidify into a fusion bond with the substrate 112. This process of applying and melting the superalloy powder mixture may be repeated to build up the additive portion 118 layer-by-layer to produce the desired superalloy component 114 (or portion thereof). It should be appreciated that the substrate 112 may correspond to a previously deposited layer and/or may correspond to an existing part made of a superalloy material or other metal. The additive portion 118 itself is considered herein to comprise a base alloy having a chemical composition corresponding to the superalloy powder mixture from which it is made.

In general, if the superalloy powder mixture contains powder particles each made of only the base alloy, the resulting additive portion may include a large number of microcracks, which may make it unsuitable for many high temperature applications (e.g., blades and guide vanes of gas turbines) unless the part is subjected to a Hot Isostatic Pressing (HIP) operation to collapse the cracks. Hot isostatic pressing is a process in which a component is subjected to high temperatures (above 482 ℃) and high gas (typically argon) pressures (above 50.7 MPa). Pressure is applied to the component from all directions (balanced) by the gas, collapsing the internal pores via plastic deformation, creep and/or diffusion bonding. An example of such HIP operations implemented in connection with solution heat treatment is set forth in U.S. patent No. 11,072,044B2, published at 2021, 7, 27, which is incorporated herein by reference in its entirety.

However, in the LAAM process, the superalloy powder mixture 102 comprises at least two different types of superalloy powders, each superalloy powder having a respective different solidus temperature. The inventors have found that by performing the described LAAM process, in which the elements constituting the desired difficult-to-weld superalloy are separated into different powders, a base alloy of another difficult-to-weld superalloy with significantly fewer microcracks can be produced via AM or welding. The reduction in microcracks may be sufficient to avoid the need to perform HIP operations in order to produce superalloy components having the following physical properties: the physical properties correspond to those superalloy components that may be obtained by operation using HIP, as well as those that may be obtained by casting a base alloy component.

For example, as shown in fig. 1, these different powders in the mixture may include a high-melting-point superalloy powder 104 and a low-melting-point superalloy powder 106, the high-melting-point superalloy powder 104 including high-melting-point superalloy powder particles, the low-melting-point superalloy powder 106 including low-melting-point superalloy powder particles, the low-melting-point superalloy powder particles having a solidus temperature that is lower than that of the high-melting-point superalloy powder. These different powders combined in predetermined proportions contain the elements in weight percent required for the final base alloy from which the additive portion is desirably made.

Once the superalloy powder mixture 102 has been used and the additive portion 118 is deposited by the additive system 100, it may be heat treated via a furnace. Such heat treatment may correspond to solution heat treatment, which is operable to substantially completely homogenize the mixing of the elements in the base alloy of the additive portion 118. In an exemplary embodiment, the solution heat treatment that at least substantially homogenizes the base alloy of the additive portion may include maintaining the base alloy at or above a solution heat treatment temperature of the base alloy for an extended period of time, e.g., 12 hours, and then cooling to room temperature. In another example, such solution heat treatment may include: heating the additive portion from room temperature to greater than 1200 ℃ (e.g., as between 1300 ℃ and 1400 ℃) at 2 ℃ to 20 ℃ per minute; maintaining the temperature of the additive portion at greater than 1200 ℃ (e.g., such as between 1300 ℃ and 1400 ℃) for 120 minutes to 1444 minutes; and cooling the additive portion of argon to room temperature. In another example (e.g., when the aluminum content of the base alloy of the additive portion is less than 4% by weight), the solution heat treatment may include: heating the additive portion from room temperature to between 1100 ℃ and 1300 ℃ at 2 ℃ to 20 ℃ per minute; maintaining the temperature of the additive portion between 1200 ℃ and 1300 ℃ for 120 minutes to 1444 minutes; and cooling the additive portion of argon to room temperature.

However, it should be appreciated that the homogenizing heat treatment may be performed by more or less steps or different steps, temperatures, heating/cooling rates and time ranges depending on the degree of homogenization required for the particular part to be produced and/or depending on the metallurgical and metallurgical differences between the high and low melting superalloys of the base alloy used to produce the additive portion. As used herein, a substantially homogenized base alloy is one such base alloy: in the base alloy, elemental atoms initially from the different high and low melting powder particles migrate in the additive portion to produce a relatively more homogeneous elemental distribution throughout the base alloy in order to provide the base alloy with the desired superalloy composition.

It should be noted that the metallurgical, chemical composition, solidus temperature, incipient melting temperature or other properties of the base alloy referred to herein are relative to the homogenized base alloy (unless otherwise indicated). Moreover, it should be understood that even though the high and low melting point superalloy powders are described as having solidus temperatures or other metallurgical properties, it should be understood that the particular superalloy metals from which these powder particles are made have these described solidus temperatures and/or other metallurgical properties described herein.

In an exemplary embodiment, each of the high melting point superalloy powder, the low melting point superalloy powder, the superalloy powder mixture, and the base alloy may have greater than 4% aluminum by weight to achieve a gamma prime volume fraction in the base alloy of greater than 30% (and thus corresponds to a difficult to weld superalloy). Also, for example, each of the high melting point superalloy powder, the low melting point superalloy powder, the superalloy powder mixture, and the base alloy may have greater than 5% aluminum by weight. In an exemplary embodiment, the base alloy obtained in the additive portion may have a gamma prime volume fraction of greater than 50%. Furthermore, in some exemplary embodiments (e.g., when the superalloy powder mixture and the resulting base alloy have an aluminum content of greater than 6% by weight), the gamma prime volume fraction of the base alloy may be greater than 70%.

As will be described in more detail below, the exemplary LAAM process is capable of producing additively manufactured or welded parts comprising a variety of different base alloys for high temperature applications (e.g., blades and guide vanes of gas turbines or other applications). The following description sets forth several exemplary chemical compositions of high and low melting point superalloy powders that may be used in the LAAM process. However, it should be appreciated that in view of the features of the LAAM process described herein, the LAAM process may be implemented with other chemical compositions of high and low melting superalloy powders having compositions that achieve similar effects to the reduction of microcracks described herein.

In exemplary embodiments, the difficult-to-weld superalloys from which the low-melting superalloy powder and the high-melting superalloy powder are made may contain aluminum and/or titanium, and may each be a high-gamma' alloy alone. However, it has been found that for gas turbine applications or other high temperature applications, higher oxidation resistance can be achieved using aluminum instead of titanium at temperatures above 1100 ℃. Thus, some of the exemplary high and low melting point superalloys shown herein may contain aluminum, but not titanium (or alternatively have a titanium content low enough so as to avoid or at least acceptably minimize oxidation resistance loss of the part in high temperature applications). However, it should be appreciated that the high and/or low melting point superalloys may contain relatively large amounts of titanium when the application does not require high oxidation resistance.

For example, to fabricate the additive portion 118 via an AM process, the additive portion 118 has a composition that does not include titanium and has similar or better operating characteristics (e.g., in a gas turbine) than CM 247 LC superalloy using casting, the following exemplary high-melting and low-melting nickel-based superalloy powders having the chemical compositions shown in table I were used in the LAAM process to produce sample pieces:

Table I-LAAM process examples

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These high and low melting point powders were mixed together in a weight ratio of about 80:20, respectively, to form a superalloy powder mixture. The resulting homogenized base alloy of the additive portion 118 (produced from such a superalloy powder mixture) may have a chemical composition (80/20 based on the weight ratio of high melting superalloy powder to low melting superalloy powder) corresponding to that shown in table I.

In an exemplary embodiment, the high melting point superalloy powder and the low melting point superalloy powder are mixed together such that their respective particles are relatively more uniformly distributed in the superalloy powder mixture. For example, such high and low melting point superalloy powders may have a substantially uniform distribution by placing the high and low melting point superalloy powders in a vessel and subjecting the vessel to vibration, rotation, and/or other mechanical action so as to more evenly distribute the different high and low melting point superalloy powder particles in the mixture such that the average variance in the weight distribution of the powders between any two halves of the mixture is less than 10%. In an exemplary embodiment, the high melting point superalloy powder and the low melting point superalloy powder may have a powder particle size distribution in a spherical morphology between 10 micrometers-60 micrometers (μm). However, it should be understood that alternative embodiments may use powders of other particle sizes and morphologies (e.g., alternatively, particle size distributions from 10 μm to 100 μm) depending on the nature of the base alloy desired and/or the characteristics of the powder bed of the SLM printer or other type of additive system.

Figures 2-4 show that cracks and voids were found to be reduced in the additive portion 118 generated using the LAAM process after modification compared to corresponding 3D printed samples generated by the same 3D printer and AM process parameters for superalloy powders containing only CM 247 LC superalloy.

For example, fig. 2 shows an image 200 of a cross section taken from a sample block 202, the sample block 202 made of CM 247 LC superalloy via an SLM 3D printer. It should be appreciated that the microstructure of the sample block 202 includes a large number of microcracks and voids that make it unsuitable for use with guide vanes and blades of a gas turbine without subsequent HIP operation. For comparison purposes, this exemplary sample block 202 of CM 247 LC superalloy is considered to have about the following chemical composition shown in table II:

table II-CM 247 LC superalloy exemplary chemical compositions and nominal ranges

FIG. 3 shows an image 300 of a cross section taken from a sample block 302, the sample block 302 being made using a superalloy powder mixture having a weight ratio of low melting superalloy powder to high melting superalloy powder of 80:20, the low melting superalloy powder and the high melting superalloy powder having the respective chemical compositions shown in Table I. The sample block 302 is generated by an SLM printer and those AM process parameters corresponding to those used to generate the sample block 202 made of CM 247 LC superalloy. Image 300 is shown after heat treating the block to homogenize the base alloy as previously described. Image 200 shows the block after a similar heat treatment. It should be appreciated that the microstructure of the sample block 302 shown in fig. 3, which is made via the LAAM process, includes significantly fewer cracks and voids than the additively manufactured CM 247 LC superalloy sample block 202 shown in fig. 2.

It should be appreciated that the reduction of cracks and voids is achieved without the need for Hot Isostatic Pressing (HIP) operations on the sample block 302 to close/collapse the cracks and voids. It should also be noted that, unlike some prior attempts to achieve weldability of difficult-to-weld nickel-base superalloys, such as described in U.S. patent No. 10,753,211B2, which was issued 8/25/2020, no ceramic additives are required in the heterogeneous composition to achieve these results.

To further clarify the reduction of cracks and voids via the LAAM process, fig. 4 shows an enlarged image 400 of a cross section of the sample block 302. In exemplary embodiments, it should be appreciated that the cross-sectional crack density (in mm/mm) of the additive portion produced via the LAAM process (before and after heat treatment and without HIP) ² Meter) is at least 50% lower on average than the crack density obtained from additive manufacturing of the corresponding sample block using a single powder made of only one of the following: CM 247 LC superalloy, high melting point superalloy, low melting point superalloy, and base alloy.

For example, cross-sectional cracks of sample blocks produced via the LAAM process (e.g., those sample blocks produced according to the chemical composition shown in table I) were evaluated via Fluorescence Penetrant Inspection (FPI). When the aspect ratio is 4 or greater and the length is greater than 10 microns, the crack is defined as having signs of elongation. The LAAM process described was found to be capable of producing a sample block that was observed to be crack-free via this crack assessment.

European patent application No. EP 3 257 956A1 published 12/20 in 2017 also shows an example of high-grade crack density obtained from additive manufacturing using CM 247 LC superalloy and MarM247 superalloy. The crack density in EP 3 257 956A1 for both CM 247 LC and MarM247 was evaluated as higher than 2mm/mm ² . Viewed from the cross section of the test block produced using the LAAM process, it is believed that the additive portion produced by the LAAM process can achieve well below 1.0mm/mm ² And may be crack-free as previously described) without the need to increase the hafnium content of the base alloy obtained to 2.4% by weight as described in EP 3 257 956a 1. For example, the sample block 302 shown in fig. 3 is achieved by a hafnium content of about 1.6% by weight (see table I). In an exemplary embodiment of the LAAM process, a superalloy powder mixture of high melting point superalloy powder and low melting point superalloy powder may be configured such that an additive portion with a base alloy is facilitated to be produced, which typically contains less than 2.0% hafnium by weight. However, alternative embodiments may produce a base alloy containing greater than 2% hafnium by weight.

Fig. 5, 6 and 7 depict graphs 500, 600, 700 plotting tensile test results 502, 602, 702 (via diamond symbols) for sample blocks made using the LAAM process. The superalloy powder mixture used to produce these sample blocks contained high and low melting superalloy powders in a weight ratio of about 80:20, the high and low melting superalloy powders having the chemical compositions shown in Table I. The LAAM sample pieces used for these tests were heat treated as described herein to homogenize the base alloy, but not hot isostatic pressed.

These graphs also plot test results 504, 604, 704 (symbolized by circles) for sample blocks made from single CM 247 LC superalloy powder (having the chemical composition shown in table II) via AM, after heat treatment of the sample blocks and after HIP to close/collapse those cracks and pores as depicted in fig. 2. For these tests, sample blocks produced by non-hot isostatic pressing LAAM and CM 247 LC superalloys of hot isostatic pressing, both were printed by an SLM 3D printer and AM process parameters substantially corresponding to those used to generate sample blocks 202 and 302. These tests were performed according to ASTM E21 (high temperature) and E8 (low temperature) standards to produce test results spanning from room temperature to over 1000 ℃. In addition, the graphs shown in fig. 5, 6, 7 also show the tensile results of the cast CM 247 LC via solid lines 506, 606, 706. These tensile results demonstrate that the LAAM process is capable of producing superalloy components (or portions thereof) having high temperature physical properties in terms of yield strength (fig. 5), tensile strength (fig. 6), and% elongation (fig. 7), without the need for HIP, which is substantially similar to components made from a single CM 247 LC superalloy powder (HIP treated) via AM, and substantially similar to components made from a cast CM 247 LC superalloy.

The inventors believe that in order to perform the LAAM process described (and achieve the described reduction of microcracks and voids without the need for HIP treatment and these described tensile results), exemplary high and low melting superalloy powders may be used, the composition of which satisfies:

the solidus temperature of the low melting superalloy powder is below the grain boundary melting temperature of the base alloy.

The solidus temperature of the low melting point superalloy powder is much lower than the solidus temperature of the high melting point superalloy powder.

As is common in the art, the term liquidus temperature corresponds to the lowest temperature when the alloy is completely liquid, while the term solidus temperature is the highest temperature (at 1 atm) when the alloy is completely solid.

For the exemplary high and low melting superalloy powders shown in table I, their respective solidus temperatures were about 1360 ℃ and 1225 ℃, respectively, which corresponds to a solidus difference of about 135 ℃ between these high and low melting superalloy powders. However, it should be appreciated that the chemical compositions of the high and low melting point superalloy powders may have other chemical compositions that produce the same base alloy or alternative base alloys, which have similar differences between solidus temperatures of the high and low melting point superalloy powders, and which achieve similar microcrack reduction when used in the exemplary LAAM process

For example, the high melting point superalloy powder may have a chemical composition that achieves a solidus temperature between 1330 ℃ and 1450 ℃, alternatively between 1350 ℃ and 1430 ℃. Further, in such exemplary embodiments, the low melting point superalloy powder may have a chemical composition that achieves a solidus temperature between 1200 ℃ and 1370 ℃, or alternatively between 1210 ℃ and 1360 ℃. For these respective exemplary ranges for the LAAM process, the solidus temperature of the low melting superalloy powder is at least 50 ℃ lower than the solidus temperature of the high melting superalloy powder.

In this example of a base alloy produced via a LAAM process and in alternative exemplary embodiments for a different base alloy described herein, the solidus temperature of the low melting superalloy powder may be about 50 ℃ to about 220 ℃, alternatively about 70 ℃ to about 200 ℃, alternatively about 90 ℃ to about 170 ℃, alternatively about 100 ℃ to about 160 ℃, alternatively about 110 ℃ to about 150 ℃, alternatively about 120 ℃ to about 140 ℃ lower than the solidus temperature of the high melting superalloy powder.

In an exemplary embodiment, the liquidus temperature of the low melting point superalloy powder may be greater than 1300 ℃. However, it should be understood that the low melting superalloy powder may have other chemical compositions yielding the same base alloy or alternative base alloys with liquidus temperatures greater than 1270 ℃, and alternatively greater than 1440 ℃.

Further, for example, the solidus temperature (about 1225 ℃) of the low-melting superalloy powder shown in Table I is considered to be 35℃to 45℃lower than the grain boundary melting temperature (considered to be between 1260℃and 1270 ℃) of the base alloy shown in Table I. However, it should be understood that the high and low melting point superalloy powders may have other chemical compositions that produce the same base alloy or alternative base alloys, with similar differences between the solidus temperature of the low melting point superalloy powder and the grain boundary melting temperature of the base alloy. In addition, it should be appreciated that different weight ratios between the high-melting superalloy powder and the low-melting superalloy powder (in addition to the 80:20 ratio for the base alloy in Table I) and/or different chemical compositions of the high-melting superalloy powder and/or the low-melting superalloy powder may produce different temperature differences between the solidus temperature of the low-melting superalloy powder and the grain boundary melting temperature of the resulting base alloy. For example, in exemplary embodiments, the low melting point superalloy powder used in the LAAM process may be 10 ℃ to 150 ℃, alternatively 10 ℃ to 100 ℃, alternatively 10 ℃ to 70 ℃, alternatively 10 ℃ to 50 ℃, alternatively 20 ℃ to 50 ℃, alternatively about 35 ℃ to 45 ℃ below the grain boundary melting temperature of the resulting base alloy.

For base alloys similar in chemical and physical properties to CM 247LC superalloy, the following examples (shown in tables III and IV) of the chemical compositions of high-and low-melting superalloys (when used to form superalloy powder mixtures in the LAAM process) enabled the reduction of microcracks shown in sample block 302 shown in fig. 3:

table III-exemplary chemical composition of high melting point superalloys

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Table IV-exemplary chemical composition of low melting superalloys

It should be noted that for the high melting point superalloys shown in Table III, the chromium content can range from about 7.7 to about 18.0. However, for applications where it is desired that the resulting part have corrosion resistance corresponding to parts made from CM 247LC superalloy, the chromium content of the high melting point superalloy may be, for example, 7.7-8.1 in weight percent. For applications where relatively higher corrosion resistance is desired, the chromium content of the high melting point superalloy may be, for example, 12.0-16.0 in weight percent.

In the example shown in table I, yttrium (Y) is optionally included to increase the adhesion of the protective layer to the base alloy. However, as shown in table III, in alternative embodiments, cerium (Ce) may be used instead of yttrium. In addition, alternative embodiments may include both yttrium and cerium.

In an exemplary embodiment, a relatively greater amount of tantalum and/or hafnium may be contained in the low-melting superalloy powder than in the high-melting superalloy powder to act as a melting point depressant, but the percentages in each powder are also sufficient to provide the final base alloy with a composition similar to CM 247 LC or any other superalloy desired to be produced by the LAAM process. For example, a high melting point superalloy powder may contain less than half of its tantalum content by weight percent as compared to the tantalum content by weight percent of the low melting point superalloy powder. Similarly, the high melting point superalloy powder may comprise less than half of its hafnium content by weight percent as compared to the hafnium content by weight percent in the low melting point superalloy powder. Also for example, the high melting point superalloy powder may comprise up to 4.5% tantalum, alternatively up to 4.0% tantalum, alternatively less than 3.5% tantalum, alternatively less than 1.9% tantalum, alternatively up to 1.0% tantalum, alternatively up to about 0.05% tantalum, alternatively 0% tantalum by weight.

It should be understood that the exemplary embodiments of superalloy chemistries described and claimed in this disclosure may contain one or more optional incidental elements and/or unavoidable impurities. In some exemplary embodiments, the total amount of any optional incidental elements may be between 0% and 1.5% by weight. In a further example, according to table V, the optional contingent element may contain one or more of the following expressed in weight% or ppm in maximum:

Table V-optional even elements

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Further, in some exemplary embodiments, the total amount of any unavoidable impurity elements may be between 0% and.01% by weight. In a further example, for these respective elements and any other elements up to about 0.001% by weight, the unavoidable impurities may generally be within the maximum amounts listed in table V. However, it should be appreciated that in further embodiments, one or more of these optional incidental elements and/or unavoidable impurities may exceed the ranges described, provided that the optional incidental elements and/or unavoidable impurities do not interfere with the ability of the LAAM process to produce an additive portion that has material properties (e.g., tensile strength, creep resistance) after heat treatment that meet the requirements of a gas turbine hot gas path part or other high temperature application and that may be used to replace a corresponding part made from a CM 247 LC superalloy or other difficult to weld superalloy via a casting process.

In exemplary embodiments of the described LAAM process, the weight ratio of high melting point superalloy powder to low melting point superalloy powder in the superalloy powder mixture may range between about 95:05 and about 51:49; alternatively between about 90:10 and about 60:40; alternatively between about 90:10 and about 70:30; alternatively between about 85:15 and about 75:25; alternatively between about 78:22 and about 82:18; alternatively about 80:20; and alternatively between about 94:06 and about 76:24. It should also be appreciated that in some embodiments, the superalloy powder mixture may include additional powders (e.g., intermediate melting point superalloy powders, which will be described in more detail later). However, in at least some example embodiments, at least 51% by weight of the additive portion may be formed from a high melting point superalloy powder and at least 5% by weight of the additive portion may be formed from a low melting point superalloy powder. In other examples, at least 70% by weight, alternatively at least 80% by weight, alternatively at least 90% by weight, alternatively at least 95% by weight, alternatively at least 99% by weight, alternatively 100% by weight of the additive portion may comprise high and low melting point superalloy powders.

Table VI illustrates exemplary chemical compositions of superalloy powder mixtures produced by the LAAM process and base alloys obtained therefrom using the exemplary high melting superalloy powders and the exemplary low melting superalloy powders shown in table III and table IV, with weight ratios between the high melting superalloy powders and the low melting superalloy powders ranging from 90:10 to 70:30. In some examples of superalloy powder mixtures, the inventors have found that tantalum content of greater than 6.2% by weight in the resulting base alloy of the additive portion may undergo remelting during heat treatment, which results in an increase in the amount or size of voids and/or cracks in the additive portion. Thus, in some examples of the LAAM process, the chemical composition of the high superalloy powder and/or the low superalloy powder and/or their proportions in the superalloy powder mixture may be configured such that the amount of tantalum obtained in the base alloy is no more than 6.2% by weight.

Table VI-exemplary chemical composition of base alloy/superalloy mixture

As previously discussed, the exemplary chemical compositions shown in table I are configured to produce a base alloy chemical composition for the additive portion that is similar to the CM 247LC superalloy, but with enhanced oxidation resistance by removing all or most of the titanium, adding aluminum, and adding a small amount of yttrium. Fig. 8 and 9 show the enhanced oxidation resistance obtained by this chemical composition.

For example, fig. 8 shows an image 800 of a cross section of a sample block 802 cast from CM 247 LC superalloy after oxidation testing, having the chemical composition shown in table II. The cast CM 247 sample block 802 was maintained at a temperature of about 1200 ℃ for about 2000 hours. The outer surface of the block undergoes substantial oxidative degradation to a depth 804 of about 850 μm.

Fig. 9 shows an image 900 of a cross section of a sample block 602 produced via an exemplary LAAM process after an oxidation test. In the same manner as the LAAM sample block 302, a superalloy powder mixture having a weight ratio of low melting point superalloy powder to high melting point superalloy powder of 80:20 was used to generate the LAAM sample block 902, the low melting point superalloy powder and the high melting point superalloy powder having the corresponding chemical compositions shown in table I. Similar to the cast CM 247 LC sample block 802, the LAAM sample block 902 was maintained at a temperature of about 1200 ℃ for about 2000 hours. The outer surface of the block also degrades. However, unlike that shown by the cast CM 247 sample block 802, oxidative degradation only occurs to a depth 904 of about 480 μm, which illustrates the significantly improved oxidation resistance of the LAAM sample block 902 for high temperature applications.

Fig. 10 shows a schematic view 1000 of a possible theory on how the LAAM process generates fewer cracks during the AM process compared to a conventional AM process. The left half shows a conventional AM process 1002 involving a single difficult-to-weld superalloy powder (e.g., CM 247 LC superalloy). The right hand side shows the LAAM process 1004. Each example shows a respective layer 1006, 1008 deposited (and melted and cooled to a solid) along a vertical axis over time. The lower portions of the layers 1006, 1008 are earlier in time and have solidified, while the upper portions of the layers 1006, 1008 are newly melted.

To help illustrate the different phases/states of these layers 1006, 1008 over time, fig. 10 (with oval icons) shows the temperature of the layers (labeled t ₀ To t ₅ ) The following schematic snapshot views 1010, 1012. For example, at temperature t ₀ The top snapshot view below (i.e., top ellipse) shows the most recent portion of the deposited layer in the molten state (just as it was melted by the laser beam or after it was melted by the laser beam). At temperature t ₁ The lower snapshot view (i.e., the second ellipse from the top) shows the portion of the layer after it begins to cool (because the laser beam has moved away from it). Further down, at temperature t ₂ To t ₅ The lower snapshot depicts a layer deposited earlier in time and having been further cooled, wherein at temperature t ₅ The earliest snapshot shown below (i.e., bottom oval) shows the fully cured portions of each layer.

Fig. 10 also depicts three vertical lines 1014, 1016, 1018 showing that several superalloys from which the layers 1006, 1008 are made are at different points in time and at different temperatures (t ₀ To t ₅ ) Possible phases/states below. These lines 1014, 1016, 1018 are shown overlaid on phase diagrams 1020, 1022, the phase diagrams 1020, 1022 generally passing through a vertical axis corresponding to temperature and corresponding to The horizontal axis of the aluminum content by weight represents the various phases/states of the liquid (L) and gamma (γ) and gamma '(γ') precipitations. For the conventional AM process 1002, line 1014 depicts a single refractory superalloy powder (e.g., CM 247 LC superalloy) located on the phase diagram 1020 based on its high aluminum content at a temperature t ₀ To t ₅ The lower phase.

For the LAAM process 1004, line 1016 depicts the high melting point superalloy (used to make layer 1008) located on phase diagram 1022 based on its aluminum content at temperature t ₀ To t ₅ The lower phase. Similarly, line 1018 depicts the low melting point superalloy (used to make layer 1008) located on phase diagram 1022 based on its aluminum content at temperature t ₀ To t ₅ The lower phase. In addition, dashed line 1024 depicts the base alloy (which is contained in the mixture layer 1008 based on the high and low melting point superalloys) at temperature t on the phase diagram 1022 based on its aluminum content ₀ To t ₅ The following phases/states.

It should be noted that the composition of the high and low melting point superalloy powders may be selected such that the LAAM process may produce a deposited base alloy layer 1008 that is similar in composition to the deposited single difficult-to-weld superalloy layer 1006 (e.g., CM 247 LC superalloy), but has no or at least significantly fewer microcracks in the layer 1008 and its underlying layers/substrates. Thus, as approximately corresponding to the horizontal position of the wire 1014 of a single difficult-to-weld superalloy, the relative horizontal position of the wires 1024 of the base alloy produced via the LAAM process is depicted in fig. 10 relative to their relative positions on the respective phase diagrams 1020, 1022 (due to their somewhat similar aluminum content).

It should also be noted that star 1026 on line 1014 corresponds to a solidus temperature at about the time when the single difficult-to-weld superalloy solidifies, which occurs at temperature t ₁ And t ₂ But well above the temperature 1030 at which the liquefied grain boundaries solidify in the difficult-to-weld superalloy. Similarly, star 1028 on line 1018 corresponds to a solidus temperature about when the low melting point superalloy solidifies, which occurs where the liquefied grain boundaries solidify in the deposited layer 1008 of the base alloyTemperature 1032 or less.

In view of these features, an exemplary LAAM process may implement one or more of the following metallurgical functions prior to heat treating the additive portion:

the low melting point superalloy fills solidification cracking (center cracking) of the deposited layer in order to reduce solidification cracking;

the low melting point superalloy enables the deposited layer to exert less strain on the previous layer grain boundaries of the Heat Affected Zone (HAZ) (the previous layer grain boundaries are liquefied when the current layer is deposited) in order to reduce grain boundary cracking; and/or

The low melting point superalloy solidifies after solidification and strength of the liquefied grain boundaries of the HAZ in order to reduce liquefaction cracking of the HAZ.

Wherein this reduction in microcracks is relative to the amount of microcracks that would otherwise occur when the additive portion cools to room temperature, the AM process is performed by stacking the deposit using only the base alloy superalloy powder (or using only the high melting superalloy powder or using only the low melting superalloy powder) without using the superalloy powder mixture.

As known in the art, grain boundary cracking corresponds to grain boundary cracking of a previous AM layer due to grain boundary liquefaction. Solidification cracking corresponds to cracking in the current AM layer due to segregation of low melting point elements into the final liquid to solidify. In addition, the HAZ corresponds to an area or region of the substrate and/or previously deposited layer that undergoes grain boundary liquefaction when the laser beam (or other energy beam) melts and deposits a new layer that is adjacent to (but not directly on) the substrate and/or previously deposited layer. HAZ cracking occurs at these melted grain boundaries in the HAZ.

Fig. 10 schematically illustrates the reduction of microcracks. For example, an example of a HAZ liquidus rupture 1034 is depicted along a single difficult-to-weld superalloy layer 1006, which may typically occur at about temperature t for a conventional AM process 1002 ₂ To t ₅ And (3) downwards. In contrast, fig. 10 shows the absence of such HAZ liquefaction cracking along layer 1008 and in its corresponding snapshot view 1012 due to the implementation of exemplary LAAM process 1004.

It should be understood that the compositions of the high and low melting point superalloy powders described herein are not intended to be limited to only these examples, but may have different compositions depending on the desired chemical composition or properties of the base alloy. For example, to produce a superalloy component (or portion thereof) having a base alloy similar to or corresponding to a particular type or brand of difficult-to-weld superalloy, and to reduce microcracking during AM, a manufacturer of the superalloy component may selectively divide the desired chemical composition of the base alloy into the high and low melting superalloy powders, each having a different solidus temperature, and capable of performing one or more of the metallurgical functions described herein to reduce microcracking. For example, the low melting point superalloys for such alternative embodiments may be configured with an element that, when incorporated in a superalloy powder mixed with a high melting point superalloy powder in a superalloy powder mixture for the LAAM process, produces the characteristics described previously such that the low melting point superalloy: filling the deposited layer with cure cracks to produce a layer substantially free of cure cracks; the prevention layer applies strain to the HAZ layer grain boundaries (and thus prevents grain boundary cracking); and/or after the liquefied grain boundaries of the HAZ solidify and acquire strength, in order to prevent liquefaction and rupture of the HAZ.

In general, a superalloy powder mixture for additive manufacturing of superalloy parts via the LAAM process may comprise greater than 40% nickel, at least 1% tantalum, and a total of greater than 4% aluminum and optionally titanium by weight, wherein the high and low melting superalloy powders each comprise at least 40% nickel and at least 1.5% aluminum by weight. In particular, such superalloy powder mixtures may comprise by weight from about 4% to about 23% chromium, from about 4% to about 20% cobalt, from 0% to about 8% titanium, from about 1.5% to about 8% aluminum, from 0% to about 11% tungsten, from 0% to about 4% molybdenum, from about 1% to about 13% tantalum, from 0% to about 0.2% carbon, from 0% to about 1% zirconium, from 0% to about 4% hafnium, from 0% to about 4% rhenium, from 0% to about 0.1% yttrium and/or cerium, from 0% to about 0.04% boron, from 0% to about 2% niobium, and the balance nickel as its primary components. It should also be appreciated that such superalloys may contain additional components, such as 0% to 1.5% of optional incidental elements and/or unavoidable impurities, such as those listed and described in table V.

In particular, the LAAM process may be implemented with a superalloy powder mixture configured to produce a base alloy corresponding to or similar to commercially available superalloys having the chemical composition of CM 247 LC superalloys as previously discussed, as well as the exemplary superalloys (and other superalloys) listed in table VII below.

Table VII-superalloys comprising tantalum (elements in weight percent)

As with the previous example of the LAAM process, to produce a base alloy having such a chemical composition (or other desired superalloy chemical composition), the superalloy powder mixture may comprise a high melting superalloy powder that may contain less than half of its tantalum content by weight percent as compared to the tantalum content by weight percent in a low melting superalloy powder. In such examples, the low melting point superalloy powder may comprise 5% to 22% tantalum by weight, alternatively, for example, 10% to 22% tantalum, alternatively, for example, 12% to 20% tantalum, alternatively, for example, 12% to 18% tantalum, while the high melting point superalloy powder (as previously discussed) may comprise up to 4.5% tantalum by weight, alternatively up to 4.0% tantalum, alternatively less than 3.5% tantalum, alternatively less than 1.9% tantalum, alternatively up to 1.0% tantalum, alternatively up to 0.05% tantalum, alternatively 0% tantalum.

Additionally, as previously discussed, the chemical composition of the high melting point superalloy powder and/or the low melting point superalloy powder and/or their proportions in the superalloy powder mixture may be further configured such that the amount of tantalum obtained in the base alloy is no more than 6.2% by weight. However, it should be understood that in alternative embodiments, the low melting point superalloy powder may be configured with greater than 6.2% tantalum by weight, for example, wherein other elements in the superalloy powder mixture prevent problems associated with remelting during heat treatment.

It should be appreciated that the high and/or low melting point superalloy powder may comprise, for example, 0% to 0.1% yttrium and/or cerium by weight, alternatively, for example, 0.03% to 0.07% yttrium and/or cerium, as discussed in the previous embodiments. Also for example, the high and/or low melting point superalloy powder may comprise, for example, 0% to 0.04% boron and 0% to 0.2% carbon by weight.

It should also be appreciated that one or more other elements other than tantalum (e.g., chromium, cobalt, titanium, aluminum, tungsten, molybdenum, carbon, zirconium, hafnium, rhenium, yttrium, cerium, boron, niobium, nickel, or other elements) may be the same or substantially the same in each of the high and low melting superalloy powders for producing the desired superalloy base alloy via the LAAM process. However, as with the previous examples of high and low melting point superalloy powders (e.g., as shown in table III, table IV), one or more of the other respective elements (other than tantalum) in these respective powders may be respectively different in weight percent to achieve respectively different solidus temperatures that are capable of achieving one or more of the metallurgical functions described herein to reduce microcracks. For example, the amount of chromium, aluminum, and molybdenum in the low-melting superalloy powder may be 0% to less than 80% (alternatively 15% to less than 70%) by weight as compared to the high-melting superalloy powder. Also for example, the amount of cobalt and tungsten in the high melting point superalloy powder may be 0% to less than 80% (alternatively 50% to less than 75%) by weight as compared to the low melting point superalloy powder.

As previously discussed, the exemplary LAAM process may also be implemented to fabricate or repair parts made of superalloys comprising titanium (e.g., 1% to 5% by weight). Examples of commercially available superalloys comprising titanium, as listed in Table VII, include PWA1480, PWA1483, inconel-738, inconel-792, inconel-939, inconel 6203, rene N4, CMSX6, CMSX11C, GTD, and GTD444 brands of superalloys. Because these exemplary superalloys contain a significant amount of titanium, the titanium content in weight percent in the low-melting superalloy powder may be higher than the titanium content in the high-melting superalloy powder to help bring the solidus temperature of the low-melting superalloy powder sufficiently lower than the high-melting superalloy powder to perform the LAAM process and produce little or no microcracking.

For example, a superalloy powder mixture for additive manufacturing of a base alloy corresponding to or substantially similar to these commercially available superalloys (having greater than 1 wt% titanium) may be configured such that the low melting superalloy powder comprises at least 7% by weight titanium (alternatively greater than 15% by weight titanium) and the high melting superalloy powder comprises less than half of its titanium content by weight as compared to the titanium content by weight in the low melting superalloy powder. For example, the low melting point superalloy powder may comprise, for example, 7% to 25% titanium by weight, alternatively, for example, 15% to 25% titanium by weight, while the high melting point superalloy powder comprises, for example, less than 2% titanium by weight, alternatively, for example, 0% to 0.05% titanium, alternatively, for example, 0% titanium by weight.

The exemplary LAAM process may also be implemented to make or repair parts made from superalloys (e.g., exemplary base alloys having the chemical compositions listed in table VI and corresponding to the chemical compositions of CM 247 LC superalloys listed in table II) containing substantial amounts of hafnium (e.g., up to 4% by weight). Because these exemplary superalloys contain a significant amount of hafnium, the hafnium content in weight percent in the low-melting superalloy powder may be configured to be higher than the hafnium content in the high-melting superalloy powder to help bring the solidus temperature of the low-melting superalloy powder sufficiently lower than the high-melting superalloy powder to perform the LAAM process and produce little or no microcracking.

For example, a superalloy powder mixture for additive manufacturing of a base alloy containing up to 4% by weight hafnium may be configured such that the low melting superalloy powder comprises at least 0.5% by weight hafnium (e.g., 3% to 12% hafnium), and the high melting superalloy powder comprises less than half of its hafnium content by weight percent as compared to the hafnium content by weight percent in the low melting superalloy powder. For example, the high melting point superalloy powder may comprise less than 1.7% hafnium by weight, alternatively for example 0% to 0.05% hafnium, alternatively for example 0% hafnium.

In addition, the exemplary LAAM process may also be implemented to make or repair difficult-to-weld superalloys comprising greater than 2% rhenium by weight, medium to high amounts of aluminum (1.5% to 8% by weight), relatively high amounts of tantalum (greater than 5% by weight), and low amounts of titanium (0% to 1% by weight). In particular, alternative embodiments of the described LAAM process may be implemented by superalloy powder mixtures configured to produce a base alloy that corresponds to or is similar to commercially available difficult-to-weld superalloys, such as the superalloys of the brands Ren 142, ren N5, and PWA 1484 listed in table VII, which are known to have excellent oxidation and creep resistance in gas turbine applications. In particular, superalloy mixtures comprising the exemplary high melting superalloy powders shown in Table VIII and the low melting superalloy powders shown in Table IX may be used to produce parts via the LAAM process, the resulting base alloy being similar to such superalloys containing a rhenium content of greater than 2% by weight.

Table VIII-high melting superalloy powder example

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Table IX-Low melting superalloy powder examples

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However, as previously discussed, it should be appreciated that alternative embodiments may include alternative chemical compositions for these high and low melting point superalloy powders, depending on the desired content of the resulting base alloy.

In alternative embodiments, one or more aspects of the LAAM process may be implemented to produce components made of a base alloy using a superalloy powder mixture that includes a relatively high amount of titanium (1% to 5% by weight) and a low to high amount of aluminum (2% to 5% by weight), but zero or low amount of tantalum (0% to 0.5% by weight). In particular, alternative embodiments may be implemented by superalloy powder mixtures configured to produce a base alloy corresponding to or similar to commercially available superalloys having chemical compositions such as those of the brands Ren 80, inconel 100, udiemt 710, udiemt 720 (as well as other superalloys containing zero or low amounts of tantalum) shown in table X.

Table X-tantalum-free superalloys (wt% element)

To produce parts containing base alloys corresponding to or similar to these superalloys, the titanium content in weight percent of the low melting superalloy powder may be configured to be higher than the high melting superalloy powder (as previously described) to help bring the solidus temperature of the low melting superalloy powder sufficiently lower than the high melting superalloy powder to improve the physical properties of the base alloy when the AM process is performed.

It should also be appreciated that in the exemplary embodiments of AM processes or welding processes described herein, each particle included in the powders described herein may generally have the same chemical composition (e.g., consistent with the elemental ranges by weight described herein). However, in some exemplary embodiments, it should be understood that the chemical composition of each particle in the powder may vary, so long as the chemical composition of the powder generally corresponds to the chemical composition described herein for that particular powder. Thus, it should also be appreciated that in some embodiments, one or both of the high and low melting point superalloy powders may itself comprise more than one type of powder mixture.

For example, the high melting point superalloy powder may comprise more than one high melting point powder, each high melting point powder having a different chemical composition, but their combination corresponds to examples of high melting point superalloy powders described herein. Further, the low-melting superalloy powder may comprise more than one low-melting powder, each low-melting powder having a different chemical composition, but their combination corresponds to examples of low-melting superalloy powders described herein. In exemplary embodiments, the element or elements may be similarly contained in different particles forming the particular powders described herein, provided that the different particles do not interfere with the ability of the LAAM process to produce lower amounts of cracks and voids as described in the exemplary embodiments. However, it should also be appreciated that in typical examples, both the high-melting superalloy powder and the low-melting superalloy powder comprise particles, wherein all or substantially all of the particles typically have the same respective chemical composition (typical differences are conventional manufacturing processes that produce powders intended to comprise the same alloy).

Further, in alternative embodiments, the superalloy powder mixture may comprise one or more intermediate melting superalloy powders, each intermediate melting superalloy powder having a solidus temperature that is between the solidus temperatures of the high melting superalloy powder and the low melting superalloy powder, provided that the amount of these intermediate melting superalloy powders does not interfere with the ability of the LAAM process to produce lower amounts of cracks and voids as described in the exemplary embodiments. For example, the amount of these intermediate melting point powders may be less than 30% by weight of the superalloy powder mixture (i.e., the portion of the base alloy/additive portion formed from the high melting point superalloy powder and the low melting point superalloy powder is at least 70% by weight). Alternatively, embodiments may contain different amounts by weight of intermediate melting point superalloy powder.

In an exemplary embodiment, such intermediate melting point superalloy powder may have the chemical composition: the chemical composition comprises all or a portion of the elements described as being included in the base alloy, the high melting point superalloy powder, and/or the low melting point superalloy powder, wherein the weight range of the elements is such that the solidus temperature of the intermediate melting point superalloy powder is between the solidus temperatures of the respective high melting point superalloy powder and low melting point superalloy powder.

Referring again to fig. 1, as previously discussed, the substrate 112 may correspond to a previously deposited layer produced from the superalloy powder mixture 102. However, it should also be appreciated that the substrate 112 may correspond to different types of superalloys and/or existing components made from the same or different types of superalloys (or some other metal other than superalloys). For example, fig. 11 shows a schematic view 1100 of the process described in fig. 1 implemented by an additive system 100 corresponding to an SLM 3D printer 1102. In this example, the substrate 112 corresponds to an existing superalloy component 1114 installed in a 3D printer. The 3D printer is shown at a point in time at which the powder layer 1104 of the superalloy powder mixture 102 has been previously deposited on the superalloy component 1114. The laser beam 1106 of the 3D printer is shown melting the deposited powder layer 1104 along the tool path 1108, with the melted layer 1110 eventually cooling to a solid layer 1112 that is fusion bonded to the superalloy component 1114. This process may then be repeated to build up additional solid layers 1112 of the base alloy superalloy that was made by melting the superalloy powder mixture 102.

The process shown in fig. 11 may be used to repair damaged existing superalloy components to correspond to refurbished superalloy components. For example, fig. 12 shows a perspective view 1200 of a superalloy component 1114 in the form of a gas turbine blade made of a conventional superalloy (e.g., CM 247 LC or another superalloy). The blade is depicted as having an upper tip portion 1202, the upper tip portion 1202 having a number of cracks 1204. It may also have oxidative damage. To repair the blade, the upper tip portion 1202 may be removed (e.g., severed via EDM) at dashed line 1206, and the remaining portion 1208 (including root 1210) of the superalloy component 1114 (without upper tip portion 1202) may be installed in a 3D printer. In this example, the newly created upper surface of the remainder 1208 (at the location of the dashed line 1206) may correspond to the upper surface of the base 112 shown in fig. 1 and the upper surface of the superalloy component 1114 shown in fig. 11.

Fig. 13 illustrates a perspective view 1300 of a superalloy component 1114, the perspective view 1300 showing the stacking of additional layers 1304 to form a refurbished blade 1302 having a replacement upper tip portion 1306. Such an alternative upper tip portion corresponds to a tip test piece. In this example, the test piece is created via a LAAM process and fused to the remainder 1208 of the superalloy component 1114. The superalloy material resulting from the LAAM process for replacing the upper tip portion 1306 may comprise a different superalloy chemical composition that exhibits superior operational properties (e.g., higher oxidation, corrosion and thermal fatigue resistance) than the original type of superalloy from which the upper tip portion 1202 was removed. For example, superalloy component 1114 in the form of a gas turbine blade may contain a superalloy of greater than 0.5% titanium by weight, and superalloy component 1114 may experience problems with high temperature oxidation at its tip. Replacement of such tips with tip test pieces, which are made from high performance superalloy powder mixtures and the resulting base alloys containing less or no titanium (e.g., 0 to 0.5% titanium, alternatively 0 to 0.05% titanium, and alternatively 0 to 0.005% titanium by weight) via the LAAM process may enable such paddles to achieve higher oxidation resistance. However, it should be understood that alternative embodiments of the superalloy powder mixture and resulting base alloy may contain an amount of titanium corresponding to CM 247 alloy (0.6% to 0.9% as shown in table II) or a higher titanium content (e.g., 0.5% to 2.9% by weight) for use in applications where oxidation resistance is less desirable. The increase in the amount of titanium in the base alloy may be achieved by increasing the amount of titanium in the exemplary low melting superalloy (e.g., up to about 5% titanium by weight).

Furthermore, the 3D printer may be configured to be able to stack up replacement upper tip portions 1306 having different designs (e.g., different cooling holes or other cooling structures), which replacement upper tip portions 1306 also enhance the operational properties of the refurbished blade 1302. Additionally, in other examples, the example LAAM process may be implemented on a newly manufactured (e.g., AM or cast) blade (having a root) or other component that is made of a first type of superalloy (e.g., CM 247 LC superalloy) or other metal (e.g., titanium) and that has no upper tip portion manufactured (e.g., cast) rather than refurbishing the blade or other superalloy component. Thus, the LAAM process may be integrated into the production of new paddles or other components having an upper tip portion made of a different type of superalloy (or other metal) using the superalloy powder mixture 102.

In a further exemplary embodiment, rather than stacking the test pieces on existing superalloy components installed within the 3D printer, the test pieces may be individually generated in the 3D printer via a LAAM process on a print bed of the 3D printer. Thus, the substrate 112 corresponds to a first layer and/or a previous layer of a test piece previously deposited and made from the superalloy powder mixture 102. In this further example, a test piece produced via the LAAM process may be brazed to an existing superalloy component or other metal component to form a desired final shape of the part. For example, the replacement upper tip portion 1306 of the paddle may be produced separately in a 3D printer and then subsequently brazed to the body of the paddle including the root. It should be understood that the term "metal component" as used herein is not intended to be limited to reference to non-superalloys, but rather should be construed broadly to correspond to components made from one or more types of metals and/or alloys and/or superalloys and/or base alloys.

In the previous example of the LAAM process, the superalloy powder mixture is described as comprising a high melting point superalloy powder and a low melting point superalloy powder. However, it is also possible to implement an AM method that uses a powder mixture comprising a high melting point superalloy powder and a eutectic powder to create an additive portion (useful for gas turbines or other high temperature applications), wherein the eutectic powder has a much lower solidus temperature than the low melting point superalloy powder with respect to the LAAM process (e.g., the solidus temperature of the eutectic powder may be 220 ℃ or more below the solidus temperature of the high melting point superalloy powder, and the liquidus temperature of the eutectic powder is below 1300 ℃).

Unlike the LAAM process, in this alternative approach, a significant amount of cure cracks and voids may form in the additive portion during additive manufacturing of the additive portion. However, during subsequent heat treatments, the portion of the additive portion formed from the eutectic powder may have a solidus temperature low enough that it is able to at least partially liquefy and fill in the solidification cracks and voids (referred to herein as crack healing) without degrading the shape of the part (and without requiring a HIP operation).

The crack healing AM process may share steps similar to the LAAM process described with respect to fig. 1, wherein the low melting superalloy powder is replaced with the eutectic powder. The high melting point superalloy powder may correspond to Gao' superalloys, such as CM 247 LC, ren 142, and N5 superalloys. The eutectic powder may mainly comprise nickel-chromium-titanium or nickel-chromium-titanium-zirconium or other eutectic powders having similar properties. The weight ratio of the high melting point powder to the eutectic powder of the superalloy powder mixture may range from about 94:06 to about 76:24, alternatively from about 94:06 to about 85:15.

In a first example of this crack healing AM process, a high melting point superalloy powder having the chemical composition shown in table XI and a nickel-chromium-titanium-zirconium eutectic powder are separately mixed together in a weight ratio of about 90:10 to form a superalloy powder mixture.

Table XI-example of crack healing AM Process

The superalloy powder mixture may be used in the crack healing AM process described to produce parts having similar operating characteristics (e.g., in a gas turbine) as cast CM 247 LC. In this example, the liquidus temperature of the nickel-chromium-titanium-zirconium eutectic powder is about 1225 ℃ which is lower than the liquidus temperature of the low melting point superalloy powder for the LAAM process.

Fig. 14 shows an image 1400 of a cross-section taken from a sample block 1402 (after heat treatment), the sample block 1402 being made using the exemplary superalloy powder mixture. Sample block 1402 is generated by an SLM printer and AM process parameters corresponding to those used to generate sample block 202 made of CM 247 LC superalloy as shown in fig. 2. Fig. 14 shows that the fracture healing occurred in the sample block 1402 to achieve a significantly smaller size/volume of the cracks and pores than those shown in the CM 247 LC sample block of fig. 2.

In an exemplary embodiment, after heat treatment, the crack healing AM process produces significantly fewer cracks and voids in the additive portion than if the AM process were performed using a single powder that corresponds to only one of the base alloy or the high melting point superalloy.

In this fracture healing example, the heat treatment (during which the fracture healing occurs) may for example comprise the step of heating the sample block above 1200 ℃ for at least 12 hours in a furnace. The heat treatment process for the crack healing AM process may further include one or more of the heat treatment steps described previously with respect to the LAAM process. However, it should be appreciated that the fracture healing heat treatment may be implemented by more or less steps or different steps, temperatures, heating/cooling rates and time ranges, depending on the degree of fracture healing (and homogenization) required for the particular part to be produced and/or depending on the chemical composition of the particular high melting superalloy powder and eutectic powder of the base alloy used to produce the additive portion.

The following examples of nickel-chromium-titanium-zirconium eutectic powder chemistry (shown in table XII) when used to form superalloy powder mixtures in combination with high melting point superalloy powder mixtures, such as CM 247 LC superalloy shown in table II, ren 142 superalloy shown in table VII, or other superalloys, enable the reduction of microcracks shown in sample block 1402 shown in fig. 14:

table XII-exemplary chemical composition of eutectic powder (Nickel-chromium-titanium-zirconium)

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An alternative embodiment may be implemented by a nickel-chromium-titanium eutectic powder having a chemical composition such as that shown in table XIII below:

table XIII-exemplary chemical composition of eutectic powder (Nickel-chromium-titanium)

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While the previous examples of the LAAM process and crack healing AM process may involve the use of SLM type 3D printers, it should be understood that alternative embodiments may implement the process with other types of additive systems, including 3D printers and/or welders. For example, the additive system 100 may include a Laser Powder Deposition (LPD) 3D printer or a Laser Metal Deposition (LMD) 3D printer, which are of the Directional Energy Deposition (DED) type using nozzles that emit laser beams to melt powder material blown from the nozzles while moving along a tool path to build up layers of superalloys. In a further example, the additive system 100 may include a Laser Wire Deposition (LWD) system that employs welding wire that similarly moves along a tool path to deposit material provided via melting of the welding wire by a laser (or other energy source).

It should be understood that the term "layer" may refer to a layer of metal powder particles or a layer of deposited metal powder that is bonded via a binder (before the metal powder has been melted and/or sintered together). Furthermore, the term "layer" may refer to an additive layer, filler, or cover layer of solidified deposited superalloy material after the powder has been melted and solidified (or sintered) into a fused connection with the substrate and/or a preceding layer. Furthermore, while the energy source 110 depicted in fig. 1 has been described as a laser emitting a laser beam, it should be understood that alternative embodiments may use other forms of energy sources to melt and fuse and/or sinter superalloy powder mixtures. For example, the energy source 110 may correspond to a current from a welder or an electron emitter that emits the energy beam 108 in the form of high-speed electrons. In other examples (e.g., an additive portion formed via a binder-based 3D printer as described subsequently with reference to fig. 16 and 17), the additive system 100 may include an energy source 110 corresponding to a furnace that thermally processes the additive portion to burn off the binder and sinter the metal powder.

In addition, it should be appreciated that the printing or welding system of DED, LPD, LMD and LWD (and adhesive-based 3D printers) may include a robotic arm (or other articulating system) that moves nozzles and/or wires (e.g., welding wire or filaments) relative to a fixed or articulating print bed on which the substrate 112 is mounted to facilitate deposition of material on the sides of the component/substrate. Thus, it should be appreciated that the phrase "stacking" does not require that the material be stacked layer by layer only in the vertical direction, but may include stacking the parts in the horizontal direction, depending on the technology of the 3D printer used. It should be appreciated that the additive system 100 discussed herein and schematically depicted in fig. 1 is intended to be construed broadly to encompass any type of 3D printer or welder system capable of producing (stacking and/or welding together) superalloy components or portions thereof in superposition using the superalloy powder mixtures described herein. Further, such robotic arms or other articulating systems that move nozzles and/or wires (e.g., welding wires or filaments) may be included in a CNC system that includes additional tools for machining components for additive manufacturing (i.e., performing solid manufacturing processes such as drilling, milling, and turning).

Fig. 15 illustrates an exemplary wire in the form of a welding wire 1500, the welding wire 1500 may be used in an LWD process to additive manufacture a component (or portion thereof) or join superalloy metal parts together. The welding wire 1500 may include a cylindrical outer sheath 1502, the outer sheath 1502 functioning as a tube that contains and encapsulates the superalloy powder mixture 1504 therein. The sheath may be formed from a relatively thin foil rolled into a tubular cored elongate body. The thickness of the foil wall of the sheath 1502 may be, for example, between 40 μm and 250 μm (or other thickness of superalloy powder mixture may be maintained).

In an exemplary embodiment, such sheath 1502 may comprise nickel or an alloy containing nickel, and may be melted (with superalloy powder mixture 1504) to form a base alloy as described herein. It should be appreciated that the chemical composition of the high-melting superalloy powder and/or the low-melting superalloy powder (or eutectic powder) forming the superalloy powder mixture 1504 may be modified as compared to the embodiments described herein to account for the portion of the nickel content (and any other elements) provided by the sheath, rather than just the superalloy powder mixture itself.

Thus, for example, if the nickel contributed by a given length of sheath 1502 provides 10% nickel by weight, which 10% nickel would form a given melt pool with a corresponding amount of superalloy powder material provided within the length of welding wire 1500, the chemical composition of the high and/or low melting superalloy powder (or eutectic powder) therein may comprise less than 10% nickel by weight. Furthermore, in each of the high-melting point superalloy powder and/or the low-melting point superalloy powder (or eutectic powder), the total amount in weight percent of the elements other than nickel may be adjusted upward (while maintaining their relative proportions to each other) to correspond to the reduction in weight percent of nickel in these powders. However, it should be understood that in other examples, only one of the high-melting superalloy powder and the low-melting superalloy powder (or eutectic powder) may be adjusted to account for the nickel provided by the sheath. Furthermore, in other embodiments, the reduction in weight percent of nickel contributed by the high and low melting point superalloy powders (or eutectic powders) may be different percentages. Further, in other examples, the adjustment of the weight percentages of some elements in the high and low melting point superalloy powders (or eutectic powders) may not increase, or may increase in an amount that is not proportional to the weight percentage adjustment for other elements (to account for the reduction of nickel in these powders).

Additionally, while the foregoing examples illustrate the implementation of the LAAM process and the crack healing AM process to produce components comprising nickel-based superalloys, it should be understood that alternative embodiments may be used to produce components comprising iron-based superalloys, cobalt-based superalloys, or chromium-based superalloys that comprise a higher percentage of iron, cobalt, or chromium than previously described.

Superalloy components 114, or portions thereof, described herein as being additively manufactured or welded may correspond to components or parts for gas turbine engines (e.g., turbine blades, guide vanes, seals, disks, combustors, compressors, and other hot gas path parts). However, it should be understood that the examples described herein may be applied to additive manufacturing or welding of any type of component or portion thereof made of superalloys including, but not limited to, reciprocating engine valves, compressors, metal working tools, turbocharger rotors and seals, rocket engines, reaction vessels, pollution control systems, and/or any other application or component that may benefit from the use of difficult-to-weld superalloys.

It should also be appreciated that exemplary embodiments may include providing, using, and/or manufacturing powders corresponding to one or more of high melting point superalloy powders, low melting point superalloy powders, eutectic powders, and superalloy powder mixtures. Furthermore, exemplary embodiments may include: the high melting point superalloy powder, the low melting point superalloy powder, and the eutectic powder are manufactured by mixing the respective high melting point superalloy or component of the low melting point superalloy at elevated temperatures in the melt in the proportions described herein, and allowing the melted mixture to cool to provide the respective high melting point superalloy and low melting point superalloy in solid form. During or subsequent to this process, these superalloys may be formed into a powder configuration.

In further exemplary embodiments of the LAAM process or crack healing AM process, the additive system 100 may include an adhesive inkjet 3D printer, a micro-dispensing 3D printer, an extrusion-based 3D printer, or other type of additive system capable of stacking layers of the metal powder in combination with an adhesive (e.g., wax, polymer, thermoplastic, acrylic, PTFE, and/or other type of adhesive) that bonds the powders together to form the shape of the desired part. Such parts may then be heat treated in a furnace to: burning out the binder; sintering the metal powder particles together; filling the pores; homogenizing the base alloy. As used herein, these 3D printing processes involving the use of adhesives are referred to herein as adhesive-based 3D printers. An example of the use of adhesive-based 3D printing to create a part (e.g., a pre-sintered preform) is shown in international publication No. WO 2021/021231 A1, which is incorporated herein by reference in its entirety. An example of an adhesive-based 3D printer that uses a micro-dispensing head to dispense an adhesive-bonded metal powder is the NScrypt 3D printer manufactured by NScrypt corporation of olando, florida, usa. However, it should be understood that other types of adhesive-based 3D printers may dispense the powder and adhesive separately (e.g., adhesive inkjet 3D printers). Other types of adhesive-based 3D printers may include 3D printers that extrude heated wires corresponding to filaments having elongated bodies. In exemplary embodiments, such filaments may be formed by combining one or more of the metal powders described herein with a binder. Such filaments may be long and flexible enough to be wound on a spool. In addition, such filaments may contain more than 50% by volume of metal powder and less than 50% by volume of binder. Examples of such adhesive-based 3D printers that may use such filaments to produce components include the Markforged Metal X3D printer manufactured by Markforged corporation of watton, ma. Examples of binders that may be combined with the metal powder to form such filaments and/or additive portions include the polymer systems described in U.S. patent No. 10,800,108B2, issued 10/13 in 2020 (e.g., including one or more of thermoplastics, polyolefins, polyethylene, polypropylene, and hydrocarbon-based waxes), which are incorporated herein by reference in their entirety. However, it should be understood that adhesive-based 3D printer processes and/or extrudable filaments used with the metal powders described herein may use other types of adhesive materials that are thermally decomposable and have minimal residue and/or that are removable with solvents.

Fig. 16 illustrates an example 1600 of an adhesive-based 3D printer process that may be used to produce metal parts using the metal powders described herein. In an initial first step 1602, an adhesive-based 3D printer 1622 may use at least one dispenser 1610 to dispense and/or form a combination of an adhesive 1614 and a superalloy powder mixture comprising a high melting point powder 1616 and a low melting point powder 1618, which combination is deposited layer by layer to build up components 1620 (shown in this example as blocks). Examples of such adhesive-based 3D printers 1622 may include a dispenser 1610 in the form of a micro-dispensing syringe that may dispense a paste formed by the combination 1612. In an alternative embodiment, the adhesive-based 3D printer 1622 may include a dispenser 1610, the dispenser 1610 corresponding to an extrusion nozzle of an extruder 1626, and the extruder 1626 may heat the filaments 1624 formed from the bond 1612 such that the filaments 1624 flow out of the nozzle. However, for an adhesive inkjet type 3D printer, the dispenser 1610 may correspond to a plurality of dispensers that respectively dispense the superalloy powder mixture and the adhesive to form the combination. In a second step 1604, the component 1620 may be heat treated in a furnace at a temperature and for an amount of time (e.g., between 300 ℃ and 500 ℃ for 30 minutes), which can burn off the adhesive 1614 (leaving the component with internal voids). In a third step 1606, the component 1620 may be heat treated in a furnace at a temperature and for an amount of time (e.g., between 1000 ℃ and 1200 ℃ for 2 hours) to solid state sinter the component. In a fourth step 1608, the component 1620 may be heat treated in a furnace at a temperature and for an amount of time that enables liquid phase sintering and homogenization of the component. For example, the component may be heated to a temperature between 1200 ℃ and 1300 ℃ and held in that temperature range for 1 minute to 60 minutes such that the portion formed by the low melting point powder 1618 melts (or eutectic powder melts) and pulls the portion formed by the high melting point superalloy powder to fill the pores and provide the component with a porosity low enough for high temperature superalloy applications (e.g., >99.9% density relative to a component having zero porosity). Continuing with the fourth step 1608, the heat treatment may be continued by maintaining the base alloy at or above the solution heat treatment temperature of the base alloy for an extended period of time (e.g., 12 hours) to substantially homogenize the base alloy of the component, followed by cooling to room temperature. For example, such solution heat treatment may include maintaining the temperature of the component between 1200 ℃ and 1250 ℃ for 120 minutes to 1444 minutes; and cooling the additive portion of argon to room temperature.

In this example described with reference to fig. 16 (and the example described later in fig. 17), the low-melting powder has a relatively lower solidus temperature than the high-melting powder. For example, the solidus temperature of the low melting point powder may be at least 50 ℃ lower than the solidus temperature of the high melting point powder. In these examples, the low melting point powder may correspond to the low melting point superalloy powder 106 described herein or the eutectic powder described herein. Further, the high melting point powder may correspond to the high melting point superalloy powder described herein or another superalloy powder. It should also be appreciated that the superalloy powder mixture in the bond 1612 may be a further example of the superalloy powder mixture 102 described herein, and that the component 1620 may be a further example of the additive portion 118 described herein, in which the additive portion 118 is formed by sequentially depositing and fusing together layers of the superalloy powder mixture via an adhesive 1714, the adhesive 1714 being included in the superalloy powder mixture in the bond 1612. In such an exemplary bond 1612, the weight ratio of high-melting superalloy powder to low-melting superalloy powder (or eutectic powder) may range between about 95:05 and about 51:49; alternatively between about 90:10 and about 60:40; alternatively between about 90:10 and about 70:30; alternatively between about 85:15 and about 75:25; alternatively between about 82:18 and about 78:22; and alternatively between about 94:06 and about 76:24.

Fig. 17 shows a further example 1700 of an adhesive-based 3D printer process that may be used to produce metal components using the metal powders described herein. In an initial first step 1702, at least one dispenser 1710 may be operated to dispense a first bond 1712 of an adhesive 1714 and a superalloy powder mixture, which includes a high melting point powder 1716, layer by layer to stack components 1720 (shown in this example as blocks). As part of this first step 1702, at least one dispenser 1710 (or a different at least one dispenser) is operated to dispense a second bond 1724 of adhesive 1714 and low melting point powder 1718 to create an additional layer or layers (referred to herein as sheet 1722) on at least a portion of the outer surface of component 1720. In a second step 1704, the component 1720 may be heat treated in a furnace at a temperature and for an amount of time (e.g., between 300 ℃ and 500 ℃ for 30 minutes) that can burn off the adhesive 1714 (leaving the component 1720 and sheet 1722 with internal voids). In a third step 1706, component 1720 and sheet 1722 may be heat treated in a furnace at a temperature and for an amount of time (e.g., between 1000 ℃ and 1200 ℃ for 2 hours) to solid state sinter component 1720 and sheet 1722. In a fourth step 1708, component 1720 and sheet 1722 may be heat treated in a furnace at a temperature and for an amount of time that enables liquid phase sintering and homogenization of the component. For example, component 1720 and sheet 1722 may be heated to a temperature between 1200 ℃ and 1300 ℃ and held in that temperature range for 1 minute to 60 minutes such that sheet 1722 formed from low melting point powder 1718 melts and is drawn into the pores of component 1720 formed from high melting point powder 1716 in order to provide the component with a porosity sufficiently low for high temperature superalloy applications (e.g., >99.9% density relative to a component having zero porosity). Continuing with the fourth step 1708, heat treatment may be continued by maintaining the base alloy at or above the solution heat treatment temperature of the base alloy for an extended period of time (e.g., 12 hours) to substantially homogenize the base alloy of the component, followed by cooling to room temperature. For example, such solution heat treatment may include maintaining the temperature of the component between 1200 ℃ and 1250 ℃ for 120 minutes to 1444 minutes; and cooling the additive portion of argon to room temperature.

These described exemplary steps shown in fig. 16 and 17 allow sintering and homogenizing of the part without melting the high melting point powder. Because the high melting point powder does not melt during the process, residual stresses that cause cracking during solidification are absent and/or significantly reduced, thereby reducing and/or minimizing voids and microcracks in the part relative to parts made directly from the base alloy additive.

In addition, in these described examples, HIP operation may not be required after part formation, as liquid phase infiltration can produce sufficiently dense structures (e.g., >99.9% density structures as previously described). In addition, by using the described process, the layer thickness may be at least 10 μm for some types of adhesive-based 3D printers. Thus, components made of high oxidation resistant superalloys may be formed and used in high temperature applications having portions/features with thicknesses less than 50 μm (e.g., superalloy foils 40-50 microns thick). In addition, these described processes (using an adhesive-based 3D printer process) can be used to produce pre-sintered preforms as described in international publication No. WO2021/021231 A1.

In further embodiments (e.g., the process described with respect to fig. 17), component 1720 may be formed from a first combination 1712 of an adhesive and a high melting point powder corresponding to a desired conventionally known superalloy (e.g., ren 142, CM 247 LC) or a high melting point superalloy described herein. The second bond 1724 comprising the binder 1714 and used to form the sheet 1722 may comprise a low melting point powder or may be a combination of a low melting point superalloy powder (or eutectic powder) and a high melting point powder, the low melting point powder corresponding to the low melting point superalloy powder (or eutectic powder) as described herein.

In examples where second bond 1724 includes both high-melting-point superalloy powder and low-melting-point superalloy powder, the weight ratio of high-melting-point superalloy powder to low-melting-point superalloy powder may range between about 05:95 and about 30:70; alternatively between about 10:90 and about 25:75; alternatively between about 15:85 and about 25:75; and alternatively between about 18:82 and about 22:78. In this example, the superalloy powder mixture of the second bond 1724 may be a further example of the superalloy powder mixture 102 described herein, and the sheet 1722 may be a further example of the additive portion 118 described herein, the additive portion 118 being formed by sequentially depositing and fusing together layers of the superalloy powder mixture via an adhesive 1714, the adhesive 1714 being included in the superalloy powder mixture in the second bond 1724.

Additionally, in many examples described herein, the heat treatment may be performed in a furnace separate from the additive system 100. Thus, embodiments of the LAAM process and crack healing process may include moving the part formed by the 3D printer to a separate furnace to facilitate heat treatment of the part.

In fig. 18, an example method 1800 is illustrated in accordance with an example LAAM process described herein, the method 1800 facilitating additive manufacturing of a superalloy component (or portion thereof). While the method is described as a series of acts being performed in a sequence, it should be understood that the method may not be limited by the order of the sequence. For example, some acts may occur in a different order than described herein unless otherwise indicated. Additionally, in some cases, one action may occur simultaneously with another action. Moreover, in some cases, not all acts may be required to implement the methodologies described herein.

The method 1800 includes an act 1802: layers of a superalloy powder mixture comprising a high melting point superalloy powder and a low melting point superalloy powder are sequentially deposited and fused together to build up the additive portion. The method may also include an act 1804 of: the additive portion is heat treated at a temperature of 1200 ℃ or greater than 1200 ℃ to form a homogenized base alloy contained in the additive portion, the base alloy having a chemical composition defined by a superalloy powder mixture.

In an exemplary embodiment of the method 1800, the superalloy powder mixture may comprise at least 51% by weight of a high melting point superalloy powder; and at least 5% by weight of a low melting point superalloy powder. The solidus temperature of the low melting point superalloy powder may be 50 ℃ to 220 ℃ lower than the solidus temperature of the high melting point superalloy powder. Each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture may have a nickel content of greater than 40% by weight and an aluminum content of at least 1.5% by weight (and alternatively an aluminum content of at least 4% by weight, and further alternatively a nickel content of greater than 45% by weight and an aluminum content of at least 5.5% by weight).

Furthermore, in an exemplary embodiment of the method 1800, the liquidus temperature of the low melting point superalloy powder may be greater than 1300 ℃.

Further, in the exemplary embodiment of method 1800, the low-melting point superalloy powder may contain at least 5% tantalum by weight (and alternatively at least 10% tantalum by weight), and the high-melting point superalloy powder may contain less than half of its tantalum content by weight as compared to the tantalum content by weight in the low-melting point superalloy powder.

Additionally, in method 1800, the high melting point superalloy powder may comprise up to 4.5% tantalum, alternatively up to 4.0% tantalum, alternatively less than 3.5% tantalum, alternatively less than 1.9% tantalum, alternatively up to 1.0% tantalum, alternatively up to 0.05% tantalum, alternatively 0% tantalum by weight.

It should be appreciated that the described method 1800 may include additional and/or alternative acts corresponding to the features and acts previously described with respect to the LAAM process.

In fig. 19, another example method 1900 is illustrated that facilitates additive manufacturing of a superalloy component in accordance with the example crack healing AM process described herein. The method includes an act 1902: layers of a superalloy powder mixture comprising a high melting point superalloy powder and a eutectic powder are sequentially deposited and fused together to build up an additive portion of the superalloy component. Additionally, the exemplary method may include an act 1904: heat treating the additive portion at a temperature of 1200 ℃ or above 1200 ℃ to heal cracks in the additive portion, wherein the heat treated additive portion defines a base alloy having a chemical composition corresponding to the superalloy powder mixture.

In an exemplary embodiment of method 1900, the solidus temperature of the eutectic powder may be 220 ℃ or more below the solidus temperature of the high melting point superalloy powder. Furthermore, each of the high melting point superalloy powder and the superalloy powder mixture may have a nickel content of greater than 40% by weight. In addition, each of the high melting point superalloy powder and the superalloy powder mixture may have a nickel content of greater than 40% by weight and an aluminum content of at least 1.5% by weight (and alternatively an aluminum content of at least 4% by weight, and further alternatively a nickel content of greater than 45% by weight and an aluminum content of at least 5.5% by weight).

It should also be appreciated that the described method 1900 may include additional and/or alternative actions that correspond to the features and actions previously described with respect to the crack healing AM process and the LAAM process.

Although exemplary embodiments of the present invention have been described in detail, those skilled in the art will understand that various changes, substitutions, variations and alterations herein disclosed may be made without departing from the spirit and scope of the invention in its broadest form.

No description of the present invention should be read as implying that any particular element, step, act, or function is an essential element that must be included in the scope of the claims: the scope of patented subject matter is defined only by the issued claims. Furthermore, unless the exact word "means for … …" is followed by a word, none of the claims are intended to be interpreted by a claim that recites a means plus function.

Further, it is to be understood that the words or phrases used herein should be construed broadly unless otherwise limited by the context clearly. For example, the terms "include", "having" and "including" and derivatives thereof, are intended to be non-limiting. The singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "or" is inclusive, meaning and/or unless the context clearly dictates otherwise. The phrases "associated with … …" and "associated with" and derivatives thereof may refer to inclusion, interconnection with … …, containment, inclusion, connection to … … or with … …, coupling to … … or with … …, communicable with … …, cooperation with … …, interleaving, juxtaposition, proximity to … …, adhesion to … … or … …, having, characteristics of … …, or the like. Furthermore, although various embodiments or configurations may be described herein, any features, methods, steps, components, etc. described with respect to one embodiment are applicable to other embodiments without specific recitation of the contrary.

Furthermore, although the terms "first," "second," "third," and the like may be used herein to connote various elements, information, functions or acts, the elements, information, functions or acts should not be limited by the terms. Rather, these numerical adjectives are used to distinguish one element, information, function or act from another. For example, a first element, information, function or act may be referred to as a second element, information, function or act, and similarly, a second element, information, function or act may be referred to as a first element, information, function or act.

In addition, the term "adjacent to … …" may mean: an element is relatively close to but not touching another element; or the element may be in contact with another portion unless the context clearly indicates otherwise. Furthermore, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise. The term "about" or "substantially" or similar terms are intended to encompass variations in size, quantity, number, quantity, and/or values of measurement results that are within standard industrial manufacturing tolerances. If no industry standard is available, twenty percent changes would fall within the meaning of these terms unless otherwise indicated.

Furthermore, open ranges, e.g., greater or less than a particular value, should be construed as having physically possible and reasonable unspecified minimum and maximum values based on the context of the ranges and examples described. For example, a limitation of less than 50% by weight (or less than 50 ppm), for example, should be interpreted as having a lower limit that can be as low as 0% by weight (or 0 ppm), respectively, unless described in a manner or by way of example expressing a different lower limit. Similarly, for example, a weight percent range of greater than 50% (or greater than 50 ppm) should be interpreted as having an upper limit that can be up to 100% (or 1 million ppm), respectively, by weight unless described in a manner or by way of example that expresses a different upper limit.

Claims

1. A superalloy powder mixture for additive manufacturing or welding of a metal component or portion thereof, the superalloy powder mixture comprising:

at least 51% by weight of a high melting point superalloy powder; and

at least 5% by weight of a low melting point superalloy powder,

wherein the solidus temperature of the low melting point superalloy powder is 50 ℃ to 220 ℃ lower than the solidus temperature of the high melting point superalloy powder, wherein each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture has a nickel content of greater than 40% by weight and an aluminum content of greater than 1.5% by weight, wherein the low melting point superalloy powder comprises at least 5% by weight tantalum, and wherein the high melting point superalloy powder comprises less than half of its tantalum content by weight as compared to the tantalum content by weight in the low melting point superalloy powder.

2. The superalloy powder mixture according to claim 1, wherein the superalloy powder mixture has a total aluminum content and optionally a titanium content of greater than 4% by weight.

3. The superalloy powder mixture of claim 1 or 2, wherein the superalloy powder mixture comprises by weight from about 4% to about 23% chromium, from about 4% to about 20% cobalt, from 0% to about 8% titanium, from about 1.5% to about 8% aluminum, from 0% to about 11% tungsten, from 0% to about 4% molybdenum, from about 1% to about 13% tantalum, from 0% to about 0.2% carbon, from 0% to about 1% zirconium, from 0% to about 4% hafnium, from 0% to about 4% rhenium, from 0% to about 0.1% yttrium and/or cerium, from 0% to about 0.04% boron, from 0% to about 2% niobium, from 0% to about 1.5% optional incidental elements and unavoidable impurities, and the balance nickel.

4. The superalloy powder mixture of any of claims 1-3, wherein each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture has an aluminum content of greater than 4.0% by weight.

5. The superalloy powder mixture according to any of claims 1 to 4, wherein the low melting point superalloy powder comprises at least 10% tantalum by weight.

6. The superalloy powder mixture according to any of claims 1 to 5, wherein the low melting point superalloy powder comprises at least 0.5% by weight hafnium, and wherein the high melting point superalloy powder comprises less than half of its hafnium content by weight percent as compared to the hafnium content by weight percent in the low melting point superalloy powder.

7. The superalloy powder mixture of any of claims 1 to 6, wherein at least one of the amount of chromium, aluminum, or molybdenum in weight percent in the low melting superalloy powder is at least 15 to 75 percent lower than the corresponding weight percent in the high melting superalloy powder.

8. The superalloy powder mixture of any of claims 1 to 7, wherein at least one of the amount of cobalt or tungsten in weight percent in the high melting point superalloy powder is at least 50 to 75 percent lower than the corresponding weight percent in the low melting point superalloy powder.

9. The superalloy powder mixture according to any of claims 1 to 8, wherein each of the high melting point superalloy powder, the low melting point superalloy powder, and the superalloy powder mixture has a nickel content of greater than 45% by weight and an aluminum content of greater than 5.5% by weight.

10. The superalloy powder mixture according to any of claims 1 to 9, wherein the low melting superalloy powder comprises at least 8% by weight aluminum.

11. The superalloy powder mixture according to any of claims 1 to 10, wherein the low melting superalloy powder comprises at least 3% hafnium by weight.

12. Superalloy powder mixture according to any of the claims 1 to 11, wherein the high melting superalloy powder comprises a maximum of 1% tantalum, in particular a maximum of 0.05% tantalum by weight.

13. The superalloy powder mixture according to any of the claims 1 to 12, wherein the high melting superalloy powder comprises a maximum of 0.05% by weight hafnium.

14. The superalloy powder mixture according to any of the claims 1 to 13, wherein the low melting superalloy powder comprises a maximum of 3.4% cobalt by weight.

15. The superalloy powder mixture according to any of claims 1 to 14, wherein the low melting point superalloy powder comprises at least 3.8% tungsten by weight.

16. The superalloy powder mixture according to any of claims 1 to 15, wherein the superalloy powder mixture comprises at least 9% by weight tungsten.

17. The superalloy powder mixture according to any of claims 1 to 16, wherein the superalloy powder mixture comprises a maximum of 6.2% tantalum.

18. The superalloy powder mixture of any of claims 1-17, wherein the low melting superalloy powder has a liquidus temperature above 1300 ℃.

19. The superalloy powder mixture according to any of the claims 1 to 18, wherein the solidus temperature of the low melting superalloy powder is 100 ℃ to 160 ℃ lower than the solidus temperature of the high melting superalloy powder, in particular 120 ℃ to 140 ℃ lower.

20. The superalloy powder mixture according to any of the claims 1 to 19, wherein the solidus temperature of the low melting superalloy powder is 10 ℃ to 150 ℃ lower than the grain boundary melting temperature of the homogenized base alloy, in particular 10 ℃ to 50 ℃ lower, the base alloy being defined by the chemical composition of the superalloy powder.

21. The superalloy powder mixture of any of claims 1-20, wherein the solidus temperature of the high melting superalloy powder is between 1350 ℃ and 1430 ℃.

22. The superalloy powder mixture of any of claims 1-21, wherein the low melting superalloy powder has a solidus temperature between 1210 ℃ and 1360 ℃.

23. The superalloy powder mixture of any of claims 1-22, wherein the superalloy powder mixture does not comprise a ceramic additive.

24. Superalloy powder mixture according to any of the claims 1 to 23, wherein the superalloy powder mixture comprises a maximum of 0.5% by weight of titanium, in particular a maximum of 0.05% by weight of titanium, further in particular a maximum of 0.005% by weight of titanium.

25. The superalloy powder mixture according to any of claims 1 to 24, wherein the superalloy powder mixture has an aluminum content of at least 6% by weight.

26. The superalloy powder mixture of any of claims 1-25, wherein the high melting point superalloy powder comprises 4.5% to 6.5% aluminum by weight.

27. The superalloy powder mixture of any of claims 1-26, wherein the low melting point superalloy powder comprises 8% to 9% aluminum by weight.

28. The superalloy powder mixture according to any of claims 1 to 27, wherein the superalloy powder mixture comprises a maximum of 2.0% by weight hafnium.

29. The superalloy powder mixture of any of claims 1-28, wherein the low melting point superalloy powder comprises 10% to 20% tantalum and 3% to 12% hafnium by weight.

30. The superalloy powder mixture according to any of claims 1 to 29, wherein the low melting point superalloy powder comprises 0.03 to 0.07 percent by weight of yttrium and/or cerium.

31. The superalloy powder mixture according to any of claims 1 to 30, wherein the low melting point superalloy powder comprises a maximum of 0.08% carbon by weight.

32. The superalloy powder mixture of claim 1, wherein the high melting superalloy powder comprises, by weight, 7.7% to 8.1% chromium, 10.6% to 11% cobalt, 4.5% to 6.5% aluminum, 10.6% to 11% tungsten, 0.3% to 0.55% molybdenum, and 0.05% to 0.08% carbon.

33. The superalloy powder mixture according to claim 1 or 32, wherein the high melting superalloy powder comprises by weight 0% to 2% titanium, 0% to 1% tantalum, 0% to 1% zirconium, 0% to 0.05% hafnium, 0% to 0.05% rhenium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron.

34. The superalloy powder mixture of any of claims 1, 32-33, wherein the low melting superalloy powder comprises 9.5% to 10.5% chromium, 2.9% to 3.4% cobalt, 8.0% to 9.0% aluminum, 3.8% to 4.3% tungsten, 0.8% to 1.2% molybdenum, 10% to 20% tantalum, and 3% to 12% hafnium by weight.

35. The superalloy powder mixture of any of claims 1, 32 to 34, wherein the low melting superalloy powder comprises 0% to 2% titanium, 0% to 0.08% carbon, 0% to 1% zirconium, 0% to 0.05% rhenium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron by weight.

36. The superalloy powder mixture of claim 1, wherein the high melting superalloy powder comprises, by weight, 5% to 7.3% chromium, 11% to 13% cobalt, 5.5% to 6.5% aluminum, 4.7% to 5.2% tungsten, 1.2% to 2.2% molybdenum, and 2% to 4.2% rhenium.

37. The superalloy powder mixture of claim 1 or 36, wherein the high melting superalloy powder comprises, by weight, 0% to 0.05% titanium, 0% to 4.5% tantalum, 0% to 0.15% carbon, 0% to 1% zirconium, 0% to 1.7% hafnium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron.

38. The superalloy powder mixture of any of claims 1, 36-37, wherein the low melting superalloy powder comprises 9.5% to 10.5% chromium, 2.9% to 3.4% cobalt, 7.0% to 9.0% aluminum, 3.8% to 4.3% tungsten, 0.8% to 1.2% molybdenum, and 12% to 22% tantalum by weight.

39. The superalloy powder mixture of any of claims 1, 36-38, wherein the low melting superalloy powder comprises, by weight, 0% to 2% titanium, 0% to 0.08% carbon, 0% to 1% zirconium, and 0% to 12% hafnium, 0% to 3.2% rhenium, 0% to 0.1% yttrium and/or cerium, and/or 0% to 0.04% boron.

40. The superalloy powder mixture of any of claims 1-23, wherein the low-melting superalloy powder comprises at least 7% titanium by weight, and wherein the high-melting superalloy powder comprises less than half of its titanium content by weight as compared to the titanium content by weight in the low-melting superalloy powder.

41. The superalloy powder mixture according to claim 1, wherein the superalloy powder mixture comprises the following components in weight-%:

the balance being nickel and optional incidental elements and unavoidable impurities.

42. The superalloy powder mixture of claim 41, wherein the superalloy powder mixture comprises from 7.8% to 8.8% chromium by weight.

43. The superalloy powder mixture of claim 41, wherein the superalloy powder mixture comprises 11.7% to 15.5% chromium by weight.

44. The superalloy powder mixture according to any of claims 1, 41 to 43, wherein the high melting superalloy powder comprises in weight percent:

45. The superalloy powder mixture according to claim 44, wherein the high melting superalloy powder comprises from 7.7% to 8.1% chromium by weight.

46. The superalloy powder mixture according to claim 44, wherein the high melting superalloy powder comprises from 12% to 16% chromium by weight.

47. The superalloy powder mixture according to any of claims 1, 41 to 46, wherein the low melting superalloy comprises the following in weight percent:

48. The superalloy powder mixture of claim 1, wherein the high melting point superalloy powder comprises the following in weight percent:

49. The superalloy powder mixture according to claim 1 or 48, wherein the low melting superalloy comprises the following in weight percent:

50. Superalloy powder mixture according to any of the claims 41 to 49, wherein the high melting superalloy powder comprises a maximum of 0.05% by weight of titanium, in particular 0.005% by weight of titanium.

51. Superalloy powder mixture according to any of the claims 41 to 50, wherein the low melting superalloy powder comprises a maximum of 0.05% by weight of titanium, in particular 0.005% by weight of titanium.

52. The superalloy powder mixture of any of claims 1-51, wherein each of the superalloy powder mixture, the high melting superalloy powder, and the low melting superalloy powder comprises from 0% to 0.01% by weight of one or more unavoidable impurities.

53. The superalloy powder mixture of any of claims 1 to 52, wherein each of the superalloy powder mixture, the high melting superalloy powder, and the low melting superalloy powder comprises from 0% to 1.5% by weight of one or more incidental elements other than chromium, cobalt, titanium, aluminum, tungsten, molybdenum, tantalum, carbon, zirconium, hafnium, rhenium, yttrium, cerium, and boron.

54. The superalloy powder mixture of claim 53, wherein the superalloy powder mixture, the high melting superalloy powder, and the low melting superalloy powder comprise one or more incidental elements selected from the group consisting of the following having respective maximum weight percentages or maximum ppm as shown:

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55. a superalloy powder mixture as in claim 54, wherein the unavoidable impurities are within a maximum amount for the respective incidental element and any other element that is at most 0.001% by weight.

56. The superalloy powder mixture of any of claims 1-55, wherein a weight ratio of the high melting point superalloy powder to the low melting point superalloy powder in the superalloy powder mixture is between 95:05 and 51:49.

57. The superalloy powder mixture according to claim 56, wherein the weight ratio of the high melting superalloy powder to the low melting superalloy powder in the superalloy powder mixture is between 90:10 and 70:30.

58. The superalloy powder mixture of claim 57, wherein the weight ratio of the high melting superalloy powder to the low melting superalloy powder in the superalloy powder mixture is between 85:15 and 75:25.

59. The superalloy powder mixture of claim 58, wherein a weight ratio of the high melting superalloy powder to the low melting superalloy powder in the superalloy powder mixture is between 82:18 and 78:22.

60. The superalloy powder mixture according to claim 56, wherein the weight ratio of the high melting superalloy powder to the low melting superalloy powder in the superalloy powder mixture is between 94:06 and 76:24.

61. A method comprising additive manufacturing of a metal part using the superalloy powder mixture of any of claims 1-60.

62. A method comprising welding metal parts using the superalloy powder mixture of any of claims 1-60.

63. The method of claim 61 or 62, further comprising heating the metal part in a furnace to at least partially homogenize a portion formed from the superalloy powder mixture.

64. The method of any one of claims 61 to 63, further comprising heating the metal part in a furnace at a temperature of 1200 ℃ or above 1200 ℃ for at least 120 minutes.

65. A method of additive manufacturing, the method comprising:

sequentially depositing and fusing together layers of the superalloy powder mixture of any of claims 1 to 60 to build up an additive portion; and

heat treating the additive portion at a temperature of 1200 ℃ or above 1200 ℃ to form a homogenized base alloy, the additive portion comprising the homogenized base alloy, the base alloy having a chemical composition defined by the superalloy powder mixture.

66. The method of claim 61 or 65, wherein the superalloy powder mixture is deposited and fused together via a Selective Laser Melting (SLM) 3D printer to form the additive portion.

67. The method of claim 61 or 65, wherein the superalloy powder mixture is deposited and fused together via a Directional Energy Deposition (DED) nozzle that provides the superalloy powder mixture and emits an energy beam that melts the superalloy powder mixture to form the additive portion.

68. The method of any of claims 61-62, 65, 67, wherein the superalloy powder mixture is deposited and fused together via a Laser Wire Deposition (LWD) system that employs welding wire to provide the superalloy powder mixture.

69. The method of claim 68, wherein the welding wire comprises a sheath of nickel or nickel alloy foil containing the superalloy powder mixture therein.

70. The method of any one of claims 65 to 69, wherein, in mixing the superalloy powderDuring sequential deposition and fusion together of layers of the article, the method includes filling the deposited superalloy with cracks and/or preventing cracking so as to reduce the overall length of cracks in the cross section of the additive portion to an average of less than 1.0mm/mm ² 。

71. The method of any one of claims 65 to 70, wherein the superalloy powder mixture has a composition that causes less microcracking of the superalloy powder mixture when the additive portion is cooled to room temperature prior to heat treating the additive portion relative to alternatively implementing a method of stacking additive portions using a powder comprising only a base alloy.

72. The method of any one of claims 65 to 70, wherein the superalloy powder mixture has a composition that causes less microcracking of the superalloy powder mixture when the additive portion is cooled to room temperature prior to heat treating the additive portion relative to alternatively implementing a method of stacking additive portions using only high melting superalloy powder that is not mixed with low melting superalloy powder.

73. The method of any one of claims 65 to 70, wherein the superalloy powder mixture has a composition that causes less microcracking of the superalloy powder mixture when the additive portion is cooled to room temperature prior to heat treating the additive portion relative to alternatively implementing a method of stacking additive portions using only low melting superalloy powder that is not mixed with high melting superalloy powder.

74. The method of any one of claims 71 to 73, wherein minor microcracking is achieved without subjecting the additive portion to a hot isostatic pressing operation.

75. The method of any one of claims 65 to 74, wherein the base alloy has a gamma prime volume fraction of greater than 30%, preferably greater than 50%, further preferably greater than 70%.

76. The method of any one of claims 65 to 75, wherein at least 70% by weight of the additive portion is formed from the high melting point superalloy powder and the low melting point superalloy powder, the balance comprising at least one intermediate melting point superalloy powder, the intermediate melting point superalloy powder being nickel-based and the solidus temperature of the intermediate melting point superalloy powder being between the solidus temperature of the respective high melting point superalloy powder and the solidus temperature of the low melting point superalloy powder.

77. The method of any of claims 65 to 76, wherein at least 95% by weight of the additive portion is formed from the high melting point superalloy powder and the low melting point superalloy powder.

78. The method of any one of claims 65 to 77, wherein the low melting point superalloy powder has a chemical composition that enables the low melting point superalloy powder to fill solidification cracks in each deposited layer prior to heat treating the additive portion so as to reduce solidification cracks in the deposited layer.

79. The method of any one of claims 65 to 78, wherein the low melting point superalloy powder has a chemical composition that enables the low melting point superalloy powder to enable each deposited layer to impart less strain to Heat Affected Zone (HAZ) layer grain boundaries prior to any heat treatment of the additive portion in order to reduce grain boundary cracking.

80. The method of any one of claims 65 to 79, wherein the low melting point superalloy powder has a chemical composition that enables the low melting point superalloy powder to solidify after liquefied grain boundaries of a Heat Affected Zone (HAZ) solidify and gain strength prior to heat treating the additive portion so as to reduce HAZ liquefaction cracking.

81. The method of claim 65, wherein the superalloy powder mixture is deposited with a binder via a binder-based 3D printer to form the additive portion, wherein at least one heat treatment is performed in at least one furnace that burns out the binder, sinters the superalloy powder mixture, at least partially fills voids in the additive portion, and at least partially homogenizes the additive portion.

82. A method of additive manufacturing, the method comprising:

dispensing a combination of a binder and the superalloy powder mixture of any of claims 1 to 60; and

heat treating the component in a furnace to: burning off the binder; solid state sintering the component; melting the low melting point superalloy powder to fill an internal void of the component; the base alloy is formed via homogenization, the component comprising the base alloy having a chemical composition defined by the superalloy powder mixture.

83. The method of claim 82, wherein the binder comprises a polymer, and wherein the bond comprises greater than 50% by volume of the superalloy powder mixture and less than 50% by volume of the binder.

84. The method of any one of claims 81 to 83, wherein the superalloy powder mixture is deposited with a binder via extrusion heated filaments comprising the binder and the superalloy powder mixture.

85. The method of any one of claims 65 to 84, wherein the additive portion is deposited on a substrate, the substrate corresponding to an existing metal component having a chemical composition that does not correspond to the base alloy.

86. The method of any one of claims 65 to 84, further comprising brazing the additive portion to a metal part.

87. The method of claim 85 or 86, wherein the metal component comprises greater than 0.05% by weight titanium, wherein the base alloy comprises a maximum of 0.05% by weight titanium.

88. The method of any one of claims 85 to 87, wherein the metal component comprises a root of a blade.

89. A method according to any one of claims 65 to 88, wherein the additive portion forms at least part of a turbine blade or turbine guide vane.

90. The method of any one of claims 82-84, wherein the adhesive comprises a thermoplastic.

91. The method of any one of claims 82-84, 90 wherein the adhesive comprises wax.

92. An extrudable filament for additive manufacturing, the extrudable filament comprising:

the superalloy powder mixture according to any of claims 1 to 60; and

a binder that binds the superalloy powder mixture together, wherein the binder comprises a polymer, wherein the filaments comprise greater than 50% by volume of the superalloy powder mixture and less than 50% by volume of the binder.

93. The filament of claim 92, wherein the adhesive comprises a thermoplastic.

94. The filament of claim 92 or 93, wherein the adhesive comprises wax.

95. A welding wire, the welding wire comprising:

a metal tubular sheath encapsulating the superalloy powder mixture of any of claims 1-60, wherein the metal sheath comprises nickel.

96. A metal part in which at least a portion of the metal part comprises a superalloy having a chemical composition corresponding to the superalloy powder mixture of any of claims 41 to 55.

97. The metal component of claim 96, wherein the metal component is a turbine blade or a guide vane.

98. The metal part of claim 96, wherein the metal part is a pre-sintered preform.

99. A high melting point superalloy comprising, by weight, about 7.7% to about 18% chromium, about 10.6% to about 11% cobalt, about 4.5% to about 6.5% aluminum, about 10.6% to about 11% tungsten, about 0.3% to about 0.55% molybdenum, about 0.05% to about 0.08% carbon, and at least 40% nickel.

100. The high melting point superalloy of claim 99, comprising by weight from 0% to about 2% titanium, from 0% to about 1% tantalum, from 0% to about 1% zirconium, from 0% to about 0.05% hafnium, from 0% to about 0.05% rhenium, from 0% to about 0.1% yttrium and/or cerium, and/or from 0% to about 0.04% boron.

101. The high melting point superalloy of claim 99 or 100, comprising, in weight percent:

102. The high melting point superalloy of any of claims 99-101, comprising a maximum of 0.01% by weight of one or more unavoidable impurities.

103. The high melting point superalloy of any of claims 99-102, comprising a maximum of 1.5% by weight of one or more incidental elements other than chromium, cobalt, titanium, aluminum, tungsten, molybdenum, tantalum, carbon, zirconium, hafnium, rhenium, yttrium, cerium, and boron.

104. The high melting point superalloy of any of claims 99-103, comprising one or more incidental elements selected from the group consisting of having respective maximum weight percentages or maximum ppm as shown:

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105. the high melting point superalloy of claim 104, wherein the unavoidable impurities are within a maximum amount for the respective incidental element and any other element up to 0.001% by weight.

106. The high melting point superalloy of any of claims 99-105, being in the physical form of a powder that can be used in a 3D printing or welding process.

107. The high melting point superalloy of any of claims 99-106 comprising 5.5 to 6.5% aluminum, particularly 5.3 to 5.8% aluminum by weight.

108. The high melting point superalloy of any of claims 99-107, comprising a maximum of 0.05% tantalum by weight.

109. The high melting point superalloy of any of claims 99-108 comprising a maximum of 0.05% titanium by weight.

110. The high melting point superalloy of any of claims 99-109, comprising 7.7% to 8.1% chromium by weight.

111. The high melting point superalloy of any of claims 99-110 comprising 12% to 16% chromium by weight.

112. The high melting point superalloy of any of claims 99-111, comprising 0.03% to 0.07% by weight of yttrium and/or cerium.

113. The high melting point superalloy of any of claims 99-112, in the form of a powder having powder particles with a powder particle size distribution between 10 microns and 100 microns.

114. A method of manufacturing the high melting point superalloy of any of claims 99-111, 113, the method comprising:

mixing components of the high melting point superalloy in a melt at an elevated temperature in a desired ratio; and

Forming powder particles in solid form comprising the high melting point superalloy, wherein at least a portion of the powder particles formed have a powder particle size distribution between 10 microns and 100 microns.

115. A low melting point superalloy comprising, by weight, about 9.5% to about 10.5% chromium, about 2.9% to about 3.4% cobalt, about 8.0% to about 9.0% aluminum, about 3.8% to about 4.3% tungsten, about 0.8% to about 1.2% molybdenum, about 10% to about 20% tantalum, about 3% to about 12% hafnium, and at least 40% nickel.

116. The low-melting superalloy of claim 115, comprising 0% to about 2% titanium, 0% to about 0.08% carbon, 0% to about 1% zirconium, 0% to about 0.05% rhenium, 0% to about 0.1% yttrium and/or cerium, and/or 0% to about 0.04% boron by weight.

117. The low-melting superalloy of claim 115 or 116, comprising, in weight percent:

118. The low-melting superalloy of any of claims 115-117, comprising a maximum of 0.01% by weight of one or more unavoidable impurity elements.

119. The low melting point superalloy of any of claims 115-118 comprising up to 1.5% by weight of one or more incidental elements other than chromium, cobalt, titanium, aluminum, tungsten, molybdenum, tantalum, carbon, zirconium, hafnium, rhenium, yttrium, cerium, and boron.

120. The low-melting superalloy of any of claims 115-119, comprising one or more incidental elements selected from the group consisting of having respective maximum weight percentages or maximum ppm as shown:

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121. the low-melting superalloy of claim 120, wherein the unavoidable impurities are within a maximum amount for the respective incidental element and any other element that is at most 0.001% by weight.

122. The low-melting superalloy of any of claims 115-121, being in the physical form of a powder that can be used in an additive manufacturing or welding process.

123. The low-melting superalloy of any of claims 115-122 comprising a maximum of 0.05% titanium by weight.

124. The low-melting superalloy of any of claims 115-123 comprising 7.0% to 9.0% hafnium by weight.

125. The low-melting superalloy of any of claims 115-124 comprising 0.03-0.07% yttrium and/or cerium by weight.

126. The low-melting superalloy of any of claims 115-125 in the form of a powder having powder particles with a powder particle size distribution between 10 microns and 100 microns.

127. A method of manufacturing the low melting point superalloy of any of claims 115-126, the method comprising:

mixing components of the low melting point superalloy in a melt at an elevated temperature in a desired ratio; and

forming powder particles in solid form comprising the low melting point superalloy, wherein at least a portion of the formed powder particles have a powder particle size distribution between 10 microns and 100 microns.

128. A low melting point superalloy comprising, by weight, about 9.5% to about 10.5% chromium, about 2.9% to about 3.4% cobalt, about 7.0% to about 9.0% aluminum, about 3.8% to about 4.3% tungsten, about 0.8% to about 1.2% molybdenum, about 12% to about 22% tantalum, and at least 40% nickel.

129. The low-melting superalloy of claim 128, comprising 0% to about 2% titanium, 0% to about 0.08% carbon, 0% to about 1% zirconium, and 0% to about 12% hafnium, 0% to about 3.2% rhenium, 0% to about 0.1% yttrium and/or cerium, and/or 0% to about 0.04% boron by weight.

130. The low-melting superalloy of claim 128 or 129, comprising, in weight percent:

131. The low-melting superalloy of any of claims 128-130, comprising a maximum of 0.01% by weight of one or more unavoidable impurity elements.

132. The low-melting superalloy of any of claims 128-131, comprising a maximum of 1.5% by weight of one or more incidental elements other than chromium, cobalt, titanium, aluminum, tungsten, molybdenum, tantalum, carbon, zirconium, hafnium, rhenium, yttrium, cerium, and boron.

133. The low-melting point superalloy of any of claims 128-132, comprising one or more incidental elements selected from the group consisting of having respective maximum weight percentages or maximum ppm as shown:

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134. the low-melting superalloy of claim 133, wherein the unavoidable impurities are within a maximum amount for the respective incidental element and any other element that is at most 0.001% by weight.

135. The low-melting superalloy of any of claims 128-134, the low-melting superalloy being in a physical form of a powder that is usable in an additive manufacturing or welding process.

136. The low-melting superalloy of any of claims 128-135, comprising a maximum of 0.05% titanium by weight.

137. The low-melting superalloy of any of claims 128-136, the low-melting superalloy being in the form of a powder having powder particles with a powder particle size distribution between 10 microns and 100 microns.

138. A method of manufacturing the low melting point superalloy of any of claims 128, 131-136, the method comprising:

forming powder particles in solid form comprising the low melting point superalloy, wherein at least a portion of the powder particles formed have a powder particle size distribution between 10 microns and 100 microns.