WO2020122992A1

WO2020122992A1 - Methods for producing metallic parts

Info

Publication number: WO2020122992A1
Application number: PCT/US2019/042737
Authority: WO
Inventors: Daniel J. SAUZA; Adam TRAVIS; James C. Mcmillen; Neville Whittle; Joseph M. Fridy
Original assignee: Arconic Inc.
Priority date: 2018-12-12
Filing date: 2019-07-22
Publication date: 2020-06-18

Abstract

Methods for producing a metallic part are provided. At least a region of an outer surface of an additively manufactured ("AM") metallic preform is sealed. Porosity of the AM metallic preform is reduced by a process comprising hot isostatic pressing, thereby forming the metallic part having a porosity less than a porosity of the AM metallic preform. Metallic part preforms also are disclosed.

Description

TITLE

METHODS FOR PRODUCING METALLIC PARTS

CROSS-REFERENCE

[0001] This application claims priority to U.S. Provisional Patent Application No.

62/778,337, which was filed on December 12, 2018. The contents of which is incorporated by reference into this specification.

FIELD OF USE

[0002] The present disclosure relates to methods for producing metallic parts.

BACKGROUND

[0003] Additively manufacturing parts can be challenging because there are various parameters which affect the final additively manufactured (“AM”) part and/or precursors to the part throughout the manufacturing process. Obtaining suitable physical properties in AM parts presents challenges.

SUMMARY

[0004] According an aspect of the present disclosure, a method for producing a metallic part is provided. At least a region of an outer surface of an AM metallic preform is sealed.

Porosity of the sealed AM metallic preform is reduced by a process comprising hot isostatic pressing, thereby forming a metallic part having a porosity less than a porosity of the AM metallic preform.

[0005] According to another aspect of the present disclosure, an AM metallic preform comprising an outer surface is provided. At least a region of the outer surface includes a sealing layer thereon sealing the region of the outer surface. A porosity of the sealing layer is less than a porosity of an interior of the AM metallic preform.

[0006] It is understood that the inventions disclosed and described in this specification are not limited to the aspects summarized in this Summary. The reader will appreciate the foregoing details, as well as others, upon considering the following detailed description of various non-limiting and non-exhaustive aspects according to this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The features and advantages of the examples, and the manner of attaining them, will become more apparent, and the examples will be better understood, by reference to the following description taken in conjunction with the accompanying drawings, wherein:

[0008] FIG. l is a flow chart illustrating a method for producing a metallic part according to the present disclosure; and

[0009] FIG. 2 is a schematic front view of a non-limiting embodiment of a metallic part according to the present disclosure.

[0010] The exemplifications set out herein illustrate certain embodiments, in one form, and such exemplifications are not to be construed as limiting the scope of the appended claims in any manner.

DETAILED DESCRIPTION OF NON-LIMITING EMBODIMENTS

[0011] Various non-limiting embodiments are described and illustrated herein to provide an overall understanding of the structure, function, and use of the disclosed methods and parts. The various non-limiting embodiments described and illustrated herein are non-limiting and non-exhaustive. Thus, the invention is not limited by the description of the various non limiting and non-exhaustive embodiments disclosed herein. Rather, the invention is defined solely by the claims. The features and characteristics illustrated and/or described in connection with various non-limiting embodiments may be combined with the features and characteristics of other embodiments. Such modifications and variations are intended to be included within the scope of this specification. As such, the claims may be amended to recite any features or characteristics expressly or inherently described in, or otherwise expressly or inherently supported by, this specification. Further, Applicant reserves the right to amend the claims to affirmatively disclaim features or characteristics that may be present in the prior art. The various non-limiting embodiments disclosed and described in this specification can comprise, consist of, or consist essentially of the features and characteristics as variously described herein.

[0012] Any patent, publication, or other disclosure material identified herein is incorporated herein by reference in its entirety unless otherwise indicated but only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material expressly set forth in this specification. As such, and to the extent necessary, the express disclosure as set forth in this specification supersedes any conflicting material incorporated by reference herein. Any material, or portion thereof, that is said to be incorporated by reference into this specification, but which conflicts with existing definitions, statements, or other disclosure material set forth herein, is only incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. Applicant reserves the right to amend this specification to expressly recite any subject matter, or portion thereof, incorporated by reference herein.

[0013] Any references herein to“various non-limiting embodiments,”“some embodiments,” “one embodiment,”“an embodiment,” or like phrases mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases“in various non-limiting embodiments,” “in some embodiments,”“in one embodiment,”“in an embodiment,” or like phrases in the specification do not necessarily refer to the same embodiment. Furthermore, the particular described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, the particular features, structures, or characteristics illustrated or described in connection with one embodiment may be combined, in whole or in part, with the features, structures, or characteristics of one or more other embodiments without limitation. Such modifications and variations are intended to be included within the scope of the present embodiments.

[0014] In this specification, unless otherwise indicated, all numerical parameters are to be understood as being prefaced and modified in all instances by the term“about,” in which the numerical parameters possess the inherent variability characteristic of the underlying measurement techniques used to determine the numerical value of the parameter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter described herein should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0015] Also, any numerical range recited herein includes all sub-ranges subsumed within the recited range. For example, a range of“1 to 10” includes all sub-ranges between (and including) the recited minimum value of 1 and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. Any maximum numerical limitation recited in this specification is intended to include all lower numerical limitations subsumed therein and any minimum numerical limitation recited in this specification is intended to include all higher numerical limitations subsumed therein. Accordingly, Applicant reserves the right to amend this specification, including the claims, to expressly recite any sub-range subsumed within the ranges expressly recited. All such ranges are inherently described in this specification.

[0016] The grammatical articles“a,”“an,” and“the,” as used herein, are intended to include “at least one” or“one or more,” unless otherwise indicated, even if“at least one” or“one or more” is expressly used in certain instances. Thus, the foregoing grammatical articles are used herein to refer to one or more than one (i.e., to“at least one”) of the particular identified elements. Further, the use of a singular noun includes the plural, and the use of a plural noun includes the singular, unless the context of the usage requires otherwise.

[0017] As used herein,“additive manufacturing” means“a process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies,” as defined in ASTM F2792-12a, entitled“Standard

Terminology for Additively Manufacturing Technologies.” Non-limiting examples of additive manufacturing processes useful in producing products from feedstocks include, for example, BJAM (binder jet additive manufacturing), DMLS (direct metal laser sintering), SLM (selective laser melting), SLS (selective laser sintering), and EBM (electron beam melting), among others.

[0018] As used herein,“powder” refers to a material comprising a plurality of particles. Powder may be used in a powder bed in an additive manufacturing system or process to produce a tailored alloy product via additive manufacturing. Powder, as used herein, may comprise a single material or a blend of two or more materials. In certain embodiments, powder can comprise shavings.

[0019] As used herein, a“median particle size” of a powder refers to the diameter at which 50% of the volume of the particles in the powder has a smaller diameter (e.g., Dso). Dio of a powder refers to the diameter at which 10% of the volume of the particles in the powder has a smaller diameter. D90 of a powder refers to the diameter at which 90% of the volume of the particles in the powder has a smaller diameter. As used herein, median particle size, Dio, and D90 are determined in accordance with ASTM standard B822. [0020] As used herein, a“preform” refers to a part precursor at any point in the process of making the part, prior to providing the final part.

[0021] As used herein, and as is understood to those having ordinary skill,“porosity” refers to the void (i.e., "empty") space in a material. Porosity can be empirically represented as fraction of the volume of voids in a material relative to the total volume of the material, e.g., as a number between 0 and 1, or as a volume percentage between 0% and 100%.

[0022] Additively manufactured (“AM”) parts can comprise undesirable properties, such as, for example, high porosity. The present disclosure provides systems and methods for producing a metallic part which can comprise a reduced porosity, if any.

[0023] Referring to FIG. 1, a method for producing a metallic part is provided. An AM metallic preform can be produced by an additive manufacturing process 102. Any appropriate additive manufacturing technique described in ASTM F2792-12a may be modified according to the present disclosure. In certain non-limiting embodiments, an additive manufacturing process includes depositing successive layers of powder and selectively melting and/or sintering the powder to create, layer-by-layer, an AM metallic preform. In one embodiment, the methods and systems according to the present disclosure are used in conjunction with a powder bed to create an AM metallic preform, such as, for example, a tailored alloy part and/or a unique structure unachievable, or more difficult to achieve, through traditional manufacturing techniques (e.g., without excessive post processing machining).

[0024] Non-limiting examples of additive manufacturing processes useful in producing AM metallic preforms from powder feedstocks include, for example, BJAM, DMLS, SLM, SLS, and EBM, among others. In certain non-limiting embodiments, an additive manufacturing process uses an EOSINT M 280 Direct Metal Laser Sintering (DMLS) additive

manufacturing system, or comparable system, available from EOS GmbH (Robert-Stirling- Ring 1, 82152 Krailling/Munich, Germany). Additive manufacturing techniques (e.g., when utilizing metallic feedstocks) may facilitate the selective heating of the feedstock above the liquidus temperature of the feedstock, thereby forming a molten pool followed by rapid solidification of the molten pool.

[0025] Any suitable feedstocks may be used in additive manufacturing processes or systems, including powder, a wire, a sheet, and combinations thereof. In various non-limiting embodiments, the feedstock may be, for example, a metallic feedstock (e.g., with additives to promote various properties, such as, for example, grain refiners and/or ceramic materials) such as, for example, a metal or metal alloy. In certain embodiments, the feedstock can be a wire selected from a ribbon and/or a tube. In various non-limiting embodiments, the metallic feedstock can be or comprise at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, a cobalt alloy, copper, a copper alloy, molybdenum, a molybdenum alloy, magnesium, a magnesium alloy, tantalum, a tantalum alloy, tungsten, a tungsten alloy, zinc, a zinc alloy, silver, a silver alloy, chromium, a chromium alloy, tin, a tin alloy, gold, a gold alloy, platinum, a platinum alloy, zirconium, and a zirconium alloy.

[0026] As used herein,“aluminum alloy” means a metal alloy comprising aluminum as the predominant alloying element. Similar definitions apply to the other metal alloys referenced herein (e.g., titanium alloy means a metal alloy having titanium as the predominant alloying element).

[0027] The median particle size of a feedstock comprising powder can be adapted for powder bed additive manufacturing. For example, the median particle size of the powder can be adapted so that the powder will spread in a uniform layer across a material deposition surface or on a previously deposited layer of powder. In certain embodiments, the powder can include a median particle size not greater than 325 pm, such as, for example, not greater than 200 pm, not greater than 275 pm, not greater than 250 pm, not greater than 225 pm, not greater than 200 pm, not greater than 175 pm, not greater than 150 pm, not greater than 125 pm, not greater than 100 pm, not greater than 90 pm, not greater than 70 pm, not greater than 10 pm, not greater than 5 pm, or not greater than 1 pm. In certain embodiments, the powder can include a median particle size of at least 50 nm, such as, for example, at least 1 pm, at least 5 pm, at least 10 pm, at least 70 pm, at least 90 pm, at least 100 pm, at least 125 pm, at least 150 pm, at least 175 pm, at least 200 pm, at least 225 pm, at least 250 pm, at least 275 pm, or at least 300 pm. In certain embodiments, the powder can include a median particle size in a range of 50 nm to 325 pm, such as, for example, 1 pm to 300 pm, 5 pm to 300 pm,

5 pm to 100 pm, 10 pm to 180 pm, 100 pm to 180 pm, 10 pm to 100 pm, 105 pm to 180 pm, 20 pm to 50 pm, 60 pm to 90 pm, 50 pm to 100 pm, 10 pm to 50 pm, 10 pm to 80 pm, 10 pm to 20 pm, or 25 pm to 50 pm. [0028] The median particle size of the powder can be compatible with the thickness of a layer formed from the powder. For example, the layer thickness can be from 1 time to 10 times the median particle size of the powder in the layer, such as, for example, 2 to 8 times the median particle size, or 2 to 4 times the median particle size. In some embodiments, the layer thickness can be 3 times the median particle size. The layer thickness can be, for example, from 100 nm to 3250 pm, such as, for example, 1 pm to 2000 pm, 10 pm to 2000 pm, 10 pm to 1000 pm, or 50 pm to 300 pm. In various non-limiting embodiments, the layer thickness can be 1000 pm.

[0029] In various non-limiting embodiments, an additive manufacturing process comprises (a) dispersing a feedstock in a material deposition region (e.g., powder in a powder bed) of an AM apparatus/system, (b) selectively heating a portion of the powder (e.g., via an energy source) to a temperature above the liquidus temperature of the powder, (c) forming a molten pool, and (d) cooling the molten pool at a cooling rate of at least 1000 °C per second, such as, for example, at least 10,000 °C per second, at least 100,000 °C per second, or at least

1,000,000 °C per second. Steps (a)-(d) may be repeated as necessary until the AM metallic preform is completed.

[0030] In other non-limiting embodiments, an additive manufacturing process comprises (a) dispersing a feedstock (e.g., metallic powder) in a material deposition region of an AM apparatus/system, (b) selectively binding the feedstock using, for example, a binder jetting module, and (c) repeating steps (a)-(b) as needed to thereby producing an AM metallic preform. Optionally, the AM metallic preform can be subjected to heating to burn off binder and thereafter sintered.

[0031] In another non-limiting embodiment, electron beam or plasma arc techniques can be utilized to produce at least a portion of an AM metallic preform. Electron beam techniques may facilitate production of larger parts than can readily be produced via laser additive manufacturing techniques. For example, a metallic wire used as a feedstock can be fed to a wire feeder component of an electron beam gun. The electron beam heats the wire above the liquidus point and deposits a molten pool of the metallic feedstock in a material deposition region of an AM apparatus/system. Thereafter, the molten pool rapidly solidifies to form a portion of an AM metallic preform. [0032] In various non-limiting embodiments, the porosity of the AM metallic preform can be at least 25 volume percent, such as, for example, at least 30 volume percent, at least 40 volume percent, or at least 50 volume percent. The porosity of the AM metallic preform can be, for example and without limitation, 55 volume percent or less, 50 volume percent or less, 40 volume percent or less, or 30 volume percent or less. The porosity of the AM metallic preform can be, for example and without limitation, in a range of 25 volume percent to 55 volume percent, such as, for example, 25 volume percent to 50 volume percent, or 30 volume percent to 55 volume percent.

[0033] Again referring to FIG. 1, at least a region of an outer surface of the AM metallic preform can be sealed 104 so that porosity underlying the region does not open onto and/or through the region. The region of the outer surface can be a portion of or all of the outer surface of the AM metallic preform. For example and without limitation, the outer surface of the AM metallic preform can comprise a sealed surface area of at least 50% (of the total surface area of the AM metallic preform), such as, for example, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99%. The outer surface of the AM metallic preform can comprise a sealed surface area of 100% or less, such as, for example and without limitation, 99% or less, 95% or less, 90% or less, 80% or less, 70% or less, or 60% or less. In various non-limiting embodiments, the outer surface of the AM metallic preform can comprise a sealed surface area in a range of 50% to 100%, such as, for example, 80% to 100% or 90% to 100%. In various non-limiting embodiments, the AM metallic preform can comprise a completely sealed outer surface ( e.g ., 100% sealed surface area).

[0034] As used herein, to“seal” at least a region of an outer surface of an article means to modify the region and, in some cases, a layer underlying the region, to thereby inhibit gas transfer from the interior of the article across the region of the outer surface. Modification of the region can comprise modifying an existing region of the outer surface to inhibit gas transfer through the existing region and/or adding on a new region of sealing material to the outer surface to inhibit gas transfer through the new region. In various embodiments, the modification of the region can comprise both modifying an existing region of the outer surface and adding on a new region of sealing material to the outer surface.

[0035] Modification of the existing region of the outer surface of the AM metallic preform can comprise at least one of heating the region of the outer surface with an energy source (e.g., re-melting a selected surface area at a selected depth), and applying a coating to at least a potion of an outer surface of an AM metallic preform and cold isostatic pressing the coated AM metallic preform.

[0036] The energy source can comprise, for example and without limitation, at least one of a laser module, an electron beam module, and a plasma module. For example, a laser module can be adapted to direct a laser beam onto and heat at least a selected region of the outer surface to fuse material in and underlying the region of the outer surface together and seal the outer surface region. An electron beam module can be adapted to direct an electron beam onto and heat at least a selected region of the outer surface to fuse material in and underlying the region of the outer surface together and seal the outer surface region. A plasma module can be adapted to direct hot plasma onto and heat at least a selected region of the outer surface to fuse material in and underlying the region of the outer surface together and seal the outer surface region. Heating at least a region of the outer surface with an energy source can re-melt material in a layer underlying the outer surface region of the AM metallic preform and create a sealing layer on the AM metallic preform. In embodiments comprising heating at least a region of the outer surface with an energy source, the sealing layer and the AM metallic preform can comprise the same composition.

[0037] In various non-limiting embodiments of a method according to the present disclosure in order to prepare the AM metallic preform for cold isostatic pressing, a coating can be applied to at least a potion of an outer surface of an AM metallic preform to provide a coated AM metallic preform. For example, the coating can comprise at least one of a polymer and an elastomer, such as, for example, rubber. In various non-limiting embodiments, applying the coating can comprise subjecting the interior of the AM metallic preform to a vacuum in order to urge the coating to conform to the outer surface of the AM metallic preform and/or remove gas from the interior of the AM metallic preform. The coated AM metallic preform can be subjected to a process including cold isostatic pressing to provide a pressed part. Thereafter, the coating can be removed from the pressed part. In various non-limiting embodiments, the coating can be mechanically removed and/or heated and vaporized. For example, the heating and vaporizing can include subjecting the coated AM metallic preform to a temperature greater than a vaporization temperature of the coating. In various non limiting embodiments, the heating and vaporizing can include subjecting the coated AM metallic preform to a temperature of at least 400°C, such as, for example, at least 500°C, at least 600°C, or at least 700°C. In certain embodiments, the heating and vaporizing can include subjecting the coated AM metallic preform to a temperature of 800°C or less, such as, for example, 700°C or less, 600°C or less, or 500°C or less. In certain embodiments, the heating and vaporizing can include subjecting the coated AM metallic preform to a temperature in a range of 400°C to 800°C, such as, for example, 500°C to 700°C, or 500°C to 800°C. The pressed part can comprise a reduced porosity compared to the AM metallic preform.

[0038] Adding a new region of sealing material to the outer surface of the AM metallic preform can comprise cladding, submerging the AM metallic preform in a molten sealing material, electroplating at least a region of the outer surface, and vapor depositing a material on at least a region of the outer surface.

[0039] Sealing the outer surface of the AM metallic preform also can comprise cladding at least a region of the outer surface with a sealing material. Cladding can comprise directed energy deposition. For example, a feedstock material can be melted by an energy source and deposited onto at least a region of the outer surface of the AM metallic preform to create a layer of sealing material, thereby inhibiting gas transfer from an interior of the preform through the region of the outer surface. The energy source can selectively add a new region onto the outer surface ( e.g ., melt a feedstock onto the outer surface). Cladding the AM metallic preform can create a sealing layer comprising sealing material on the AM metallic preform.

[0040] The sealing material can comprise a composition which is the same as or different than a composition of the AM metallic preform. In certain non-limiting embodiments, the sealing material can comprise a metal or metal alloy. In various non-limiting embodiments, the sealing material can comprise at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, a cobalt alloy, copper, a copper alloy, molybdenum, a molybdenum alloy, magnesium, a magnesium alloy, tantalum, a tantalum alloy, tungsten, a tungsten alloy, zinc, a zinc alloy, silver, a silver alloy, chromium, a chromium alloy, tin, a tin alloy, gold, a gold alloy, platinum, a platinum alloy, zirconium, and a zirconium alloy. In various non-limiting embodiments, the sealing material can comprise a melting point no greater than the elevated temperature utilized in step 106 described herein. [0041] Sealing at least a region of the outer surface of the AM metallic preform, in various non-limiting embodiments, can comprise submerging the AM metallic preform in a molten sealing material to contact at least a region of the outer surface of the AM metallic preform with the molten sealing material. Thereafter, the molten sealing material can be solidified on at least the region of the outer surface. A composition of the AM metallic preform can comprise a melting point greater than a melting point of a sealing material for use in a molten bath. For example, and without limitation, the melting point of the composition of the AM metallic preform can be at least 20°C greater than the melting point of a sealing material for use in a molten bath, such as, for example, at least 30°C greater, at least 50°C greater, or at least 100°C greater. In various non-limiting embodiments, the melting point of the composition of the AM metallic preform can be no more than 500°C greater than the melting point of a sealing material for use in a molten bath, such as, for example, no more than 100°C greater, no more than 50°C greater, or no more than 20°C greater. In various non-limiting embodiments, the melting point of the composition of the AM metallic preform can be greater than the melting point of a sealing material for use in a molten bath, and the difference in the melting points can be, for example, in a range of 20°C to 500°C, such as, for example, 30°C to 500°C, or 50°C to 500°C. For example, in certain non-limiting

embodiments of a method herein, an AM metallic preform can comprise AhoSiMg alloy having a melting point of at least 800°C, and a bath of sealing material can contain molten AlMg alloy or molten AlZn alloy with a melting point in a range of 655°C to 710°C.

Submerging the AM metallic preform in the molten sealing material can create a sealing layer on a surface region of the AM preform.

[0042] In various non-limiting embodiments, sealing at least a region of the outer surface of the AM metallic preform can comprise electroplating at least a region of the outer surface.

For example, at least a region of the outer surface of the AM metallic preform can be electroplated with a sealing material. Electroplating the AM metallic preform can create a sealing layer comprising sealing material on the AM metallic preform.

[0043] In various non-limiting embodiments, sealing at least a region of the outer surface of the AM metallic preform can comprise vapor depositing a material on at least a region of the outer surface. For example, the vapor deposition can comprise at least one of sputtering a material (e.g., in a vacuum chamber) onto the region of the outer surface, thermally spraying a material onto the region of the outer surface, and cold spraying the material onto the region of the outer surface. Vapor deposition can create a sealing layer comprising sealing material on the AM metallic preform.

[0044] A sealing layer created according to various non-limiting embodiments herein can comprise a thickness of at least 1 pm, such as, for example, at least 5 pm, at least 10 pm, at least 20 pm, at least 40 pm, at least 50 pm, at least 100 pm, at least 200 pm, at least 500 pm, at least 1000 pm, or at least 2000 pm. For example, and without limitation, the sealing layer can comprise a thickness of 2000 pm or less, such as, for example, 1000 pm or less, 500 pm or less, 200 pm or less, 100 pm or less, 50 pm or less, 40 pm or less, 20 pm or less, 10 pm or less, or 5 pm or less. For example, and without limitation, the sealing layer can comprise a thickness in a range of 1 pm to 2000 pm, such as, for example, 1 pm to 1000 pm or 1 pm to 40 pm.

[0045] Porosity of the AM metallic preform can be reduced by a process comprising hot isostatic pressing (“HIP”) the sealed AM metallic preform to form a metallic part having a porosity less than a porosity of the AM metallic preform 106. In various non-limiting embodiments, a porosity of the pressed part can be further reduced by HIP. HIP can comprise subjecting the AM metallic preform to an elevated temperature and elevated isostatic gas pressure in a vessel in order to urge the porosity of the AM metallic preform to close. Those having ordinary skill will readily be able to conduct a HIP treatment on a sealed AM metallic preform without further detailed discussion.

[0046] An elevated temperature used to HIP a sealed AM metallic preform in a method according to the present disclosure can be, for example and without limitation, at least 450°C, such as, for example, at least 500°C, at least 600°C, at least 1000°C, at least 1300°C, or at least 1500°C. In various non-limiting embodiments, the elevated temperature can be 2000°C or less, such as, for example, 1500°C or less, 1300°C or less, 1000°C or less, 600°C or less, or 500°C or less. In certain embodiments, the elevated temperature can be in a range of 450°C to 2000°C, such as, for example, 500°C to 1500°C or 450°C to 1500°C.

[0047] As understood by those having ordinary skill, the gas used in a HIP vessel can be an inert gas, such as, for example, argon. In various non-limiting embodiments, the elevated isostatic gas pressure used in the HIP process can be at least 7,000 pounds per square inch (psi), such as, for example, at least 10,000 psi, at least 15,000 psi, at least 20,000 psi, at least 40,000 psi, or at least 50,000 psi. In certain embodiments, the elevated isostatic gas pressure can be 60,000 psi or less, such as, for example, 50,000 psi or less, 40,000 psi or less, 20,000 psi or less, 15,000 psi or less, or 10,000 psi or less.

[0048] In various non-limiting embodiments, the AM metallic preform can be sintered prior to hot isostatic pressing the AM metallic preform.

[0049] HIP can comprise deforming the AM metallic preform to form the metallic part. For example, HIP can change the shape, porosity, and/or density of the AM metallic preform. In various non-limiting embodiments, the porosity of the metallic part formed by the HIP step can be 10 volume percent or less, such as, for example, 5 volume percent or less, 1 volume percent or less, or 0.1 volume percent or less.

[0050] A porosity, pi, of the metallic part can be less than a porosity, p2, of the AM metallic preform prior to the reducing porosity of the AM metallic preform to form the metallic part. For example, and without limitation, ! can be at least 50% less than p2, such as for example, at least 60% less, at least 70% less, at least 80% less, at least 90% less, at least 95% less, or at least 99% less than p2.

[0051] Referring to FIG. 2, an AM metallic preform 200 is provided. The AM metallic preform 200 comprises an outer surface 202 wherein at least a region 204 of the outer surface 202 includes a sealing layer 206 thereon sealing the region 204 of the outer surface 202. A porosity, if any, of the sealing layer 206 can be less than a porosity of an interior 208 of the AM metallic preform 200.

[0052] The sealing layer 206 comprises at least one of a re-melted layer of the AM metallic preform 200 and a sealing material. The interior 208 of the AM metallic preform 200 can comprise a composition that is the same as or different than a composition of the sealing layer 206. The interior 208, for example, can comprise a metal or metal alloy. The interior 208 can be or comprise at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, a cobalt alloy, copper, a copper alloy, molybdenum, a molybdenum alloy, magnesium, a magnesium alloy, tantalum, a tantalum alloy, tungsten, a tungsten alloy, zinc, a zinc alloy, silver, a silver alloy, chromium, a chromium alloy, tin, a tin alloy, gold, a gold alloy, platinum, a platinum alloy, zirconium, and a zirconium alloy. In various non-limiting embodiments, a melting point of the interior 208 of the AM metallic preform 200 can be greater than a melting point of the sealing material in the sealing layer 206. [0053] In certain embodiments, a porosity, pi , of the sealing layer 206 can be less than a porosity, p4 , of the interior 208. For example, and without limitation, pi can be at least 50% less than p4 , such as for example, at least 60% less, at least 70% less, at least 80% less, at least 90% less, at least 95% less, or at least 99% less than p4.

[0054] In various non-limiting embodiments, the porosity of the sealing layer 206 can be 10 volume percent or less, such as, for example, 5 volume percent or less, 1 volume percent or less, or 0.1 volume percent or less.

[0055] Production and Processing

[0056] In certain embodiments, the metallic part or a precursor of the part may be subject to any appropriate dissolving (e.g., homogenization), working, and/or precipitation hardening steps. If employed, the dissolving and/or the working steps may be conducted on an intermediate form (i.e., precursor) of the metallic part and/or may be conducted on a final form of the metallic part. If employed, the precipitation hardening step is generally conducted relative to the final form of the metallic part.

[0057] After or during production, a metallic part may be deformed (e.g., by one or more of rolling, extruding, forging, stretching, compressing). The final deformed product may have, for instance, improved properties due to the tailored regions and thermo-mechanical processing of the final deformed part. Thus, in some embodiments, the final part is a wrought part, wherein the word“wrought” refers to the working (hot working and/or cold working) of the metallic part, and wherein the working occurs to provide an intermediate and/or final form of the metallic part. In other approaches, the final part is a non-wrought product, i.e., is not worked during or after the additive manufacturing process. In these non- wrought product embodiments, any appropriate number of dissolving and precipitating steps may still be utilized.

[0058] Product Applications

[0059] The resulting metallic parts made in accordance with the methods described herein may be used in a variety of product applications such as commercial end-uses in industrial applications, in consumer applications (e.g., consumer electronics and/or appliances), or in other areas. For example, the metallic parts can be utilized in at least one of the aerospace field (e.g., an aerospace component), automotive field (e.g., an automotive component), transportation field (e.g., a transportation component), or building and construction field (e.g., a building component or construction component). In certain embodiments, the metallic parts can be configured as at least one of an aerospace component, an automotive component, a transportation component, and a building and construction component.

[0060] In one embodiment, a metallic part made using a process comprising a method according to the present disclosure can be utilized in an elevated temperature application, such as in an aerospace or automotive vehicle. In one embodiment, a metallic part can be utilized as an engine component in an aerospace vehicle (e.g., in the form of a blade, such as a compressor blade incorporated into the engine). In another embodiment, a metallic part made using a process comprising a method according to the present disclosure can be used as a heat exchanger for the engine of the aerospace vehicle. The aerospace vehicle including the engine component/heat exchanger may subsequently be operated. In one embodiment, a metallic part made using a process comprising a method according to the present disclosure can be an automotive engine component. The automotive vehicle including an automotive component (e.g., engine component) may subsequently be operated. For instance, the metallic part may be used as a turbocharger component (e.g., a compressor wheel of a turbocharger, where elevated temperatures may be realized due to recycling engine exhaust back through the turbocharger), and the automotive vehicle including the turbocharger component may be operated. In another embodiment, a metallic part made using a process comprising a method according to the present disclosure may be used as a blade in a land- based (stationary) turbine for electrical power generation, and the land-based turbine included the metallic part may be operated to generate electrical power. In certain embodiments, a metallic part made using a process comprising a method according to the present disclosure can be utilized in defense applications, such as in body armor or in armored vehicles (e.g., armor plating). In other embodiments, the metallic part can be utilized in consumer electronic applications, such as in consumer electronics such as laptop computer cases, battery cases, cell phones, cameras, mobile music players, handheld devices, computers, televisions, microwaves, cookware, washers/dryers, refrigerators, and sporting goods, among others.

[0061] In another aspect, a metallic part made using a process comprising a method according to the present disclosure can be utilized in a structural application, such as, for example, an aerospace structural application or an automotive structural application. For instance, the metallic part may be formed into various aerospace structural components, including floor beams, seat rails, fuselage framing, bulkheads, spars, ribs, longerons, and brackets, among others. In another embodiment, the metallic part can be utilized in an automotive structural application. For instance, the metallic part can be formed into various automotive structural components including nodes of space frames, shock towers, and subframes, among others. In one embodiment, the metallic part can be a body-in-white automotive product.

[0062] In another aspect, the metallic part made using a process comprising a method according to the present disclosure can be utilized in an industrial engineering application. For instance, the metallic part or products may be formed into various industrial engineering products, such as tread-plate, tool boxes, bolting decks, bridge decks, and ramps, among others.

[0063] Various aspects of the invention according to the present disclosure include, but are not limited to, the aspects listed in the following numbered clauses.

1. A method for producing a metallic part comprising:

sealing at least a region of an outer surface of an additively manufactured metallic preform; and

reducing porosity of the additively manufactured metallic preform by a process comprising hot isostatic pressing, thereby forming the metallic part having a porosity less than a porosity of the additively manufactured metallic preform.

2. The method of clause 1, wherein sealing at least a region of the outer surface comprises heating at least a region of the outer surface with an energy source.

3. The method of clause 2, wherein the energy source is at least one of a laser module, an electron beam module, and a plasma module.

4. The method of any one of clauses 1-3, wherein sealing at least a region of the outer

surface comprises cladding at least a region of the outer surface with a sealing material.

5. The method of clause 4, wherein a composition of the sealing material is the same as a composition of the additively manufactured metallic preform. The method of any one of clauses 4-5, wherein a composition of the sealing material is different than a composition of the additively manufactured metallic preform. The method of any one of clauses 4-6, wherein cladding at least a region of the outer surface utilizes directed energy deposition. The method of any one of clauses 1-7, wherein sealing at least a region of the outer surface comprises:

submerging the additively manufactured metallic preform in a molten sealing material to contact at least a region of the outer surface with the molten sealing material; and

solidifying the molten sealing material on the at least a region of the outer surface. The method of clause 8, wherein a composition of the additively manufactured metallic preform comprises a melting point greater than a melting point of the molten sealing material. The method of any one of clauses 1-9, wherein sealing at least a region of the outer surface comprises electroplating at least a region of the outer surface. The method of any one of clauses 1-10, wherein sealing at least a region of the outer surface comprises vapor depositing a sealing material on at least a region of the outer surface. The method of any one of clauses 1-11 comprising:

producing an additively manufactured metallic preform;

applying a coating comprising at least one of a polymer and an elastomer to at least a potion of an outer surface of the additively manufactured metallic preform to provide a coated additively manufactured metallic preform;

cold isostatic pressing the coated additively manufactured metallic preform to provide a pressed part; and

removing the coating from the pressed part and hot isostatic pressing the pressed part. The method of clause 12, wherein removing the coating from the pressed part comprises at least one of mechanically removing the coating and heating and vaporizing the coating. The method of any one of clauses 1-13, further comprising sintering the additively manufactured metallic preform prior to hot isostatic pressing the additively manufactured metallic preform. The method of any one of clauses 1-14, wherein hot isostatic pressing comprises deforming the additively manufactured metallic preform. The method of any one of clauses 1-15, wherein the porosity of the additively

manufactured metallic preform is in a range of 25 volume percent to 55 volume percent. The method of any one of clauses 1-16, wherein the porosity of the metallic part is no greater than 10 volume percent. The method of any one of clauses 1-17, wherein the porosity of the metallic part is at least 50 percent less than the porosity of the additively manufactured metallic preform prior to the reducing porosity of the additively manufactured metallic preform. The method of any one of clauses 1-18, wherein the additively manufactured metallic preform comprises at least one of a metal and a metal alloy. The method of any one of clauses 1-19, wherein the additively manufactured metallic preform comprises at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, and a cobalt alloy. The method of any one of clauses 1-20, wherein the metallic part is configured as at least one of an aerospace component, an automotive component, a transportation component, and a building and construction component.

The method of any one of clauses 1-21, wherein the method further comprises:

producing the additively manufactured metallic preform by at least one additive manufacturing process selected from binder jet additive manufacturing, electron beam melting additive manufacturing, direct metal laser sintering additive manufacturing, selective laser melting additive manufacturing, and selective laser sintering additive manufacturing. An additively manufactured metallic preform comprising an outer surface, wherein at least a region of the outer surface includes a sealing layer sealing the region of the outer surface, and wherein a porosity of the sealing layer is less than a porosity of an interior of the additively manufactured metallic preform. The additively manufactured metallic preform of clause 23, wherein the sealing layer comprises at least one of a re-melted layer and a sealing material. The additively manufactured metallic preform of any one of clauses 23-24, wherein the sealing layer comprises the sealing material, and a composition of the sealing material is the same as a composition of the additively manufactured metallic preform. The additively manufactured metallic preform of any one of clauses 23-25, wherein the sealing layer comprises the sealing material, and a composition of the sealing material is different than a composition of the additively manufactured metallic preform. The additively manufactured metallic preform of any one of clauses 23-26, wherein the sealing layer comprises the sealing material, and the sealing material comprises at least one of a polymer and an elastomer. The additively manufactured metallic preform of any one of clauses 23-27, wherein the sealing layer comprises the sealing material, and a melting point of the interior of the additively manufactured metallic preform is greater than a melting point of the sealing material. The additively manufactured metallic preform of any one of clauses 23-28, wherein the porosity of the interior of the additively manufactured metallic preform is in a range of 25 volume percent to 55 volume percent. The additively manufactured metallic preform of any one of clauses 23-29, wherein the porosity of the sealing layer is less than 10 volume percent. 31. The additively manufactured metallic preform of any one of clauses 23-30, wherein the additively manufactured metallic preform comprises at least one of a metal and a metal alloy.

32. The additively manufactured metallic preform of any one of clauses 23-31, wherein the additively manufactured metallic preform comprises at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, and a cobalt alloy.

33. The additively manufactured metallic preform of any one of clauses 23-32, wherein the additively manufactured metallic preform is produced by at least one additive

manufacturing process selected from binder jet additive manufacturing, electron beam melting additive manufacturing, direct metal laser sintering additive manufacturing, selective laser melting additive manufacturing, and selective laser sintering additive manufacturing.

[0064] One skilled in the art will recognize that the herein described methods, processes, systems, apparatus, components, devices, operations/actions, and/or objects, and the discussion accompanying them, are used as examples for the sake of conceptual clarity and that various configuration modifications are contemplated. Consequently, as used herein, the specific examples/embodiments set forth and the accompanying discussion are intended to be representative of their more general classes. In general, use of any specific exemplar is intended to be representative of its class, and the non-inclusion of specific components, devices, operations/actions, and objects should not be taken as limiting. While the present disclosure provides descriptions of various specific aspects for the purpose of illustrating various aspects of the present disclosure and/or its potential applications, it is understood that variations and modifications will occur to those skilled in the art. Accordingly, the invention or inventions described herein should be understood to be at least as broad as they are claimed and not as more narrowly defined by particular illustrative aspects provided herein.

Claims

CLAIMS What is claimed is:

1. A method for producing a metallic part comprising:

2. The method of claim 1, wherein sealing at least a region of the outer surface comprises heating at least a region of the outer surface with an energy source.

3. The method of claim 2, wherein the energy source is at least one of a laser module, an electron beam module, and a plasma module.

4. The method of any one of claims 1-3, wherein sealing at least a region of the outer

5. The method of claim 4, wherein a composition of the sealing material is the same as a composition of the additively manufactured metallic preform.

6. The method of any one of claims 4-5, wherein a composition of the sealing material is different than a composition of the additively manufactured metallic preform.

7. The method of any one of claims 4-6, wherein cladding at least a region of the outer

surface utilizes directed energy deposition.

8. The method of any one of claims 1-7, wherein sealing at least a region of the outer

surface comprises:

solidifying the molten sealing material on the at least a region of the outer surface.

9. The method of claim 8, wherein a composition of the additively manufactured metallic preform comprises a melting point greater than a melting point of the molten sealing material.

10. The method of any one of claims 1-9, wherein sealing at least a region of the outer

surface comprises electroplating at least a region of the outer surface.

11. The method of any one of claims 1-10, wherein sealing at least a region of the outer surface comprises vapor depositing a sealing material on at least a region of the outer surface.

12. The method of any one of claims 1-11 comprising:

producing an additively manufactured metallic preform;

removing the coating from the pressed part and hot isostatic pressing the pressed part.

13. The method of claim 12, wherein removing the coating from the pressed part comprises at least one of mechanically removing the coating and heating and vaporizing the coating.

14. The method of any one of claims 1-13, further comprising sintering the additively

manufactured metallic preform prior to hot isostatic pressing the additively manufactured metallic preform.

15. The method of any one of claims 1-14, wherein hot isostatic pressing comprises

deforming the additively manufactured metallic preform.

16. The method of any one of claims 1-15, wherein the porosity of the additively

manufactured metallic preform is in a range of 25 volume percent to 55 volume percent.

17. The method of any one of claims 1-16, wherein the porosity of the metallic part is no greater than 10 volume percent.

18. The method of any one of claims 1-17, wherein the porosity of the metallic part is at least 50 percent less than the porosity of the additively manufactured metallic preform prior to the reducing porosity of the additively manufactured metallic preform.

19. The method of any one of claims 1-18, wherein the additively manufactured metallic preform comprises at least one of a metal and a metal alloy.

20. The method of any one of claims 1-19, wherein the additively manufactured metallic preform comprises at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, and a cobalt alloy.

21. The method of any one of claims 1-20, wherein the metallic part is configured as at least one of an aerospace component, an automotive component, a transportation component, and a building and construction component.

22. The method of any one of claims 1-21, wherein the method further comprises:

producing the additively manufactured metallic preform by at least one additive manufacturing process selected from binder jet additive manufacturing, electron beam melting additive manufacturing, direct metal laser sintering additive manufacturing, selective laser melting additive manufacturing, and selective laser sintering additive manufacturing.

23. An additively manufactured metallic preform comprising an outer surface, wherein at least a region of the outer surface includes a sealing layer sealing the region of the outer surface, and wherein a porosity of the sealing layer is less than a porosity of an interior of the additively manufactured metallic preform.

24. The additively manufactured metallic preform of claim 23, wherein the sealing layer comprises at least one of a re-melted layer and a sealing material.

25. The additively manufactured metallic preform of any one of claims 23-24, wherein the sealing layer comprises the sealing material, and a composition of the sealing material is the same as a composition of the additively manufactured metallic preform.

26. The additively manufactured metallic preform of any one of claims 23-25, wherein the sealing layer comprises the sealing material, and a composition of the sealing material is different than a composition of the additively manufactured metallic preform.

27. The additively manufactured metallic preform of any one of claims 22-26, wherein the sealing layer comprises the sealing material, and the sealing material comprises at least one of a polymer and an elastomer.

28. The additively manufactured metallic preform of any one of claims 23-27, wherein the sealing layer comprises the sealing material, and a melting point of the interior of the additively manufactured metallic preform is greater than a melting point of the sealing material.

29. The additively manufactured metallic preform of any one of claims 23-28, wherein the porosity of the interior of the additively manufactured metallic preform is in a range of 25 volume percent to 55 volume percent.

30. The additively manufactured metallic preform of any one of claims 23-29, wherein the porosity of the sealing layer is less than 10 volume percent.

31. The additively manufactured metallic preform of any one of claims 23-30, wherein the additively manufactured metallic preform comprises at least one of a metal and a metal alloy.

32. The additively manufactured metallic preform of any one of claims 23-31, wherein the additively manufactured metallic preform comprises at least one of titanium, a titanium alloy, aluminum, an aluminum alloy, nickel, a nickel alloy, iron, an iron alloy, cobalt, and a cobalt alloy.

33. The additively manufactured metallic preform of any one of claims 23-32, wherein the additively manufactured metallic preform is produced by at least one additive manufacturing process selected from binder jet additive manufacturing, electron beam melting additive manufacturing, direct metal laser sintering additive manufacturing, selective laser melting additive manufacturing, and selective laser sintering additive manufacturing.