CN113403553B

CN113403553B - Method for preparing zirconium-based metallic glass by selective laser melting and product

Info

Publication number: CN113403553B
Application number: CN202110683809.9A
Authority: CN
Inventors: 贾延东; 马昕迪; 王刚; 孙康
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2022-01-18
Anticipated expiration: 2041-06-21
Also published as: CN113403553A

Abstract

The invention discloses a method for preparing zirconium-based metallic glass by selective laser melting and a product, belonging to the technical field of metallic glass manufacture, wherein the method comprises the following steps: weighing Zr, Cu, Ni, Al and Nb according to the atomic ratio of 57: 15.4: 12.6: 10: 5, and crushing after melting to obtain alloy powder; then, performing selective laser melting printing to obtain zirconium-based metallic glass; the invention adopts selective laser melting to prepare Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅The zirconium-based metallic glass has excellent mechanical properties, the modulus of the zirconium-based metallic glass is distributed at 105Gpa, the hardness can reach more than 7Gpa, and the zirconium-based metallic glass is printed in a complex form such as a grid structure, so that the edge of the grid structure is neat, and the structure is compact and has good formability, thereby solving the difficulty caused by the room-temperature brittleness of the zirconium-based metallic glass prepared by the traditional casting method to the processing, and developing a new direction for the processing and the application of the metallic glass.

Description

Method for preparing zirconium-based metallic glass by selective laser melting and product

Technical Field

The invention belongs to the technical field of metal glass manufacturing, and particularly relates to a method for preparing zirconium-based metal glass by selective laser melting and a product.

Background

The metallic glass is also called amorphous alloy, is a novel glass state material combined by metal bonds, has a series of outstanding mechanical and physical properties such as high strength, high hardness, corrosion resistance, wear resistance, irradiation resistance and the like due to the absence of crystal defects in the traditional meanings such as dislocation, grain boundary and the like, and has huge application prospect when being used as a high-speed kinetic energy weapon material and a high-performance space protection material. The conventional methods for metallic glass include a meteorological deposition method, a single-roller melt-spinning wire throwing method, an electric arc melting and water-cooling copper mold suction casting method and the like. The metallic glass prepared by the methods is mostly low-dimensional materials such as wires, films, belts and the like or small-size block materials. Due to the special forming mode of preparing the metal glass by casting, the internal microstructure of the metal glass has non-uniformity. Because the uneven structure of the metal glass has no rule and statistical significance, the shear band is usually caused to collapse macroscopically, which is shown in the fact that the metal glass has serious room temperature brittleness, so that the metal glass is difficult to machine and form, and further the industrial application of the metal glass is limited. The selective laser melting method is a process of positioning and melting powder through high-energy laser and stacking and forming layer by layer, the technology can break through the size limitation of the metal glass caused by the brittleness, the problem of difficulty in processing the material is solved, and the forming cost of the metal glass material is greatly reduced.

Zr-Cu-Ni-Al-Nb (Vit106a for short: Zr)₅₇Cu_15.4Ni_12.6Al₁₀Nb₅) The metal glass is one of more classical systems, and the zirconium-based metal glass system does not contain toxic, harmful and noble metal elements, and has the characteristics of high glass forming capacity, good thermal stability, excellent mechanical property and the like, so that the component is selected for forming.

Disclosure of Invention

The invention provides a method for preparing zirconium-based metallic glass by selective laser melting and a product thereof, which aim to solve the problem that the zirconium-based metallic glass cannot be machined due to room temperature brittleness in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a method for preparing zirconium-based metallic glass by selective laser melting, which comprises the following steps: weighing Zr, Cu, Ni, Al and Nb according to the atomic mol ratio of 57: 15.4: 12.6: 10: 5, and crushing after melting to obtain alloy powder; and then carrying out laser printing to obtain the zirconium-based metallic glass.

Preferably, the purities of the Zr, Cu, Ni, Al and Nb are all more than 99.99 wt.%.

Preferably, the crushing is carried out by gas atomization.

Preferably, the method further comprises the operation of screening the alloy powder to obtain powder with the particle size of 15-53 mu m, and then drying the powder for 3 hours at 70 ℃ under the vacuum condition after obtaining the alloy powder.

Preferably, the laser printing is performed by using selective laser melting forming equipment, and the specific steps are as follows:

cleaning and sand blasting the substrate by taking a pure Cu material as the substrate;

placing alloy powder into a powder cylinder, installing the base plate subjected to sand blasting treatment in a forming cylinder, adjusting the position of a scraper, spreading powder according to the powder amount of 150 mu m/layer until the base plate is fully spread with the alloy powder, and closing a cavity door;

constructing a three-dimensional model of zirconium-based metallic glass to be prepared, introducing slicing software, setting the number and the placement positions of printed parts, setting the thickness of a powder layer, the laser power, the scanning speed, the scanning path and the scanning angle, slicing, introducing the sliced parts into equipment software, closing an equipment forming cavity, introducing argon to remove oxygen, opening a laser, and starting printing after the laser is stabilized;

and after printing is finished, closing the laser and the argon, and cooling to room temperature to obtain the zirconium-based metallic glass.

Preferably, the oxygen is removed until the oxygen concentration in the molding cavity is less than 100 ppm.

Preferably, the thickness of the powder layer is 25 μm/layer, the laser power is 84-100 w, the scanning speed is 900mm/s, the scanning angle is 67 degrees, and the scanning path is in a stripe shape.

The invention also provides the zirconium-based metallic glass prepared by the method, and the composition of the zirconium-based metallic glass is Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅。

Compared with the prior art, the invention has the following beneficial effects:

the invention adopts selective laser melting to prepare Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅The zirconium-based metallic glass has excellent mechanical property, the modulus of the zirconium-based metallic glass is distributed at 105Gpa, the hardness can reach more than 7Gpa, the zirconium-based metallic glass is printed in a complex form such as a grid structure, the edge of the grid structure is found to be neat, the structure is compact and has good formability, thereby solving the processing difficulty caused by room-temperature brittleness, and the zirconium-based metallic glass is metallic glassThe processing and application of the glass opens up a new direction.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 shows the Vit106a of example 1: zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅Scanning the shape of the zirconium-based metallic glass powder;

fig. 2 is a schematic view of the working principle of the selective laser melting forming device adopted in embodiment 1, wherein 1-argon shielding gas, 2-scraper, 3-powder, 4-powder cylinder, 5-forming cylinder, 6-substrate, 7-printing sample, 8-laser emitter, 9-laser, 10-galvanometer scanning system, 11-computer 3D design and slicing software.

FIG. 3 is an XRD pattern of the metal powder obtained in step (1) of example 1 and the zirconium-based metallic glass prepared in examples 1 to 5;

FIGS. 4(a) - (e) are sequential results of fitting the XRD patterns of the zirconium-based metallic glasses prepared in examples 1-5 with an internal amorphous structure at 33-43 ℃;

FIG. 5 is a statistical graph of hardness and modulus of the nano-indentation test results of zirconium-based metallic glasses prepared in examples 1 to 5, wherein (a) is a statistical graph of hardness and (b) is a statistical graph of modulus;

FIG. 6 is a schematic diagram showing the grid structure of the zirconium-based metallic glass produced in example 3.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

Example 1

Zr based metallic glass Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅The preparation method comprises the following steps:

(1) zr, Cu, Ni, Al and Nb with the purity of more than 99.99 wt% are weighed according to the atomic mol ratio of 57: 15.4: 12.6: 10: 5.

In the atomizing equipment, high-speed inert gas argon gas flow is adopted to impact the pre-alloyed alloy in a molten state, the molten alloy is crushed through the gas flow impact, and metal powder with fine size and round shape is formed under the action of the surface tension of the liquid.

Zr prepared by gas atomization method₅₇Cu_15.4Ni_12.6Al₁₀Nb₅(Vit106a) the metallic glass particles have a typical spherical structure, the powder morphology is shown in FIG. 1, the surface of the metallic glass particles is adhered or surrounded with a plurality of small-particle satellite particle powders, and the elements are uniformly distributed without obvious segregation according to the energy spectrum result.

(2) And (2) screening the metal powder obtained in the step (1) through a screen of 300 meshes and a screen of 1000 meshes to ensure that the particle size of the powder used in the printing process is 15-53 mu m, placing the screened powder in a glass dish after the screening is finished, putting the glass dish into a vacuum oven, and drying the powder for 3 hours at the temperature of 70 ℃.

(3) The working principle of the printer adopting HBD-100 model of Hanbang laser technology Limited, Guangdong province is shown in figure 2. Drawing a sample to be prepared into a three-dimensional model by drawing software, exporting the three-dimensional model in an STL format (11 in figure 2), setting the thickness of a powder layer to be 25 mu m, setting the laser power to be 84w, selecting the scanning speed to be 900mm/s, selecting a scanning path to be a strip mode, selecting a scanning angle to be 67 degrees, setting different parameters on the same substrate, and slicing after setting, wherein the size of the sample is 10mm x 5mm, and the Magics slicing software is imported, and the placing positions and the quantity are set.

(4) Cleaning a Cu substrate (6 in figure 2) for forming by using alcohol to remove surface impurities, performing sand blasting after the Cu substrate is dried, then installing and fixing the Cu substrate on a forming cylinder (5 in figure 2) and performing leveling operation on the Cu substrate to ensure that the substrate and a platform in a cavity are positioned on the same plane, adding a proper amount of metal powder (3 in figure 2) dried in the step (2) into a powder cylinder (4 in figure 2), adjusting the position of a scraper (2 in figure 2), and performing powder paving operation for multiple times according to the powder amount of 150 mu m/layer until the powder can completely pave the whole substrate.

(5) And (3) introducing a slicing software program into software corresponding to the equipment, closing the molding cavity, introducing protective gas argon (1 in figure 2) to perform oxygen removal treatment so as to enable the oxygen concentration in the molding cavity to be lower than 100ppm, opening a laser, and waiting for the laser to be stable and start printing.

In the printing process, a scraper uniformly lays metal powder (powder above a powder cylinder 3 in fig. 2) in a powder cylinder on a forming substrate, a laser emitter (8 in fig. 2) emits laser (9 in fig. 2), the laser selectively melts the metal powder on the substrate through a galvanometer scanning system (10 in fig. 2) according to preset parameters, the powder cylinder rises by one printing layer thickness every time the forming cylinder reduces by one printing layer thickness, so that the scraper lays the metal powder with one printing layer thickness on a forming platform, and the operation is repeated repeatedly, and finally a forming sample (7 in fig. 2) of a required part can be prepared.

The main process challenge in producing large zirconium based metallic glasses is that a certain high cooling rate must be achieved, otherwise the alloy will crystallize before cooling to room temperature. Bulk metallic glasses are typically made by an arc melting copper mold suction casting process, limited by the law of thermal transfer, in which the material away from the surface cools more slowly than the material near the outer surface. This therefore amounts to an upper limit for the casting thickness. Additive manufacturing (3D printing) is a manufacturing method by material accumulation from bottom to top, building up designed parts layer by layer. Thus, the cooling during the additive manufacturing technique is also layer-by-layer cooling. Since the cooling rate can be controlled, the size limit in the manufacture of metallic glass products can be broken.

(6) And after printing is finished, closing the laser and the argon, and cooling for more than 2 hours to ensure that the powder in the forming cylinder is completely cooled to room temperature. The cavity door is opened, the forming cylinder is raised to the upper limit through the equipment control system, and the redundant powder is swept to a recovery cavity in the equipment by a brush. Sucking away the redundant dust in the equipment by a dust collector, taking the substrate down, and separating the sample on the substrate from the matrix in a wire cutting mode to obtain the Zr-based metallic glass Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅。

Examples 2 to 5

The embodiments 2 to 5 are different from the embodiment 1 in the laser power in the step (3), and the laser powers of the embodiments 2 to 5 are respectively as follows: 88w, 92w, 96w and 100 w.

Effect verification

The metal glass sample with the thickness of 2mm obtained by printing in the examples 1-5 is roughly ground by #400, #600 and #800 sandpaper on the bottom surface, finely ground by #1000, #1200, #1500 and #2000 sandpaper on the upper surface, and analyzed by X-ray diffraction analysis method by taking the finely ground upper surface as a reference surface, and the relevant parameters of X-ray diffraction include: the working voltage is 40KV, the measurement range is 10-90 degrees, the scanning speed is 4 degrees/min, meanwhile, the metal powder obtained in the step (1) of the embodiment 1 is subjected to X-ray diffraction analysis according to the parameters, the result is shown in figure 3, as can be seen from figure 3, the large cooling speed can be realized by adopting an airflow impact mode, and according to the X-ray diffraction result (XRD) of the powder, an obvious diffuse peak is formed at 38 degrees, which indicates that the metal glass powder prepared by the method is in a completely amorphous structure; the samples corresponding to the process parameters in examples 1-5 all appeared a little crystallization, and NiZr was embedded in the amorphous matrix₂，CuZr₂Isophase zirconium-based metallic glass composite material, and meanwhile, the peak shape of the sample corresponding to the process parameters of the example 1 is similar to that of the powder state, and the powder is in an ideal glassy structure, thereby indicating that the printing at the laser power of 84w obtains a product closest to the glassy structure. Fitting a function according to equation (1), pseudo-Voigt peak shape:

fitting 84w, 88w, 92w, 96w and 100w of XRD curves of the corresponding samples at 33 degrees to 43 degrees, and fitting the amorphous structure in the samples. And calculating the amorphous content ratio of the five samples by calculating the ratio of the peak area after crystallization to the fitted amorphous peak area of the corresponding angle interval, wherein the fitting results are shown in fig. 4(a) - (e). The results are shown in table 1:

TABLE 1

Sample name

84w

88w

92w

96w

100w

Amorphous content

88.16％

81.63％

84.67％

77.45％

70.92％

And after the structural characterization is finished, cold embedding the sample, exposing the finely ground upper surface, grinding the back surface of the cold embedded sample by using an automatic sample grinding machine, ensuring that the gradient of the whole embedded sample plane is not more than 1 degree, and then polishing the upper surface of the sample. Ultrasonically cleaning the polished sample by using alcohol, and then testing the hardness modulus of the sample by adopting Imicro nano indentation equipment of KLA company, wherein the maximum load of the nano indentation is 20mN, and the strain rate is 0.2s^-1The load-holding time is 5s, and the test result shows that the modulus of the Vit106a metallic glass prepared in the examples 1-5 is 104-106 GPa, the hardness is 7.3-7.5 GPa, as shown in FIG. 5, the modulus of the sample prepared by the same-component suction casting is 98-102 GPa, and the hardness is 6.3-6.7 GPa, so that the modulus and the hardness of the metallic glass prepared in the examples 1-5 are higher than those of the same-component metallic glass prepared by suction casting, which indicates that the Selective laser melting technology (SLM) is a fast melting and fast solidifying method by utilizing metal powder under the heat action of laser beamThe technology leads the crystal phase to be introduced into the amorphous system in the printing process, thereby improving the mechanical property of the material.

The structural information of an XRD curve and mechanical property parameters measured by nano-indentation are combined, an experimental scheme with the power of 92w and the laser scanning rate of 900mm/s is selected as an optimal parameter, a certain amorphous content and a higher hardness value are ensured in the parameter, gridding structural design is carried out through 3D software, and a grid structure scanning picture is shown in figure 6, and the fact that the edge of the grid structure is neat and the structure is compact and good in formability can be found in figure 6.

The above description is only for the preferred embodiment of the present invention, and the protection scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention, the technical solution and the inventive concept of the present invention equivalent or change within the technical scope of the present invention.

Claims

1. A method for preparing zirconium-based metallic glass by selective laser melting is characterized by comprising the following steps: weighing Zr, Cu, Ni, Al and Nb according to the atomic ratio of 57: 15.4: 12.6: 10: 5, and crushing after melting to obtain alloy powder; then, carrying out laser printing to obtain zirconium-based metallic glass;

the laser power of the laser printing is 84-92W.

2. The method of claim 1, wherein the purities of Zr, Cu, Ni, Al, and Nb are all above 99.99 wt.%.

3. The method of claim 1, wherein the disruption is by aerosolization.

4. The method according to claim 1, further comprising an operation of sieving the alloy powder to obtain powder having a particle size of 15 to 53 μm after obtaining the alloy powder, and then baking the powder at 70 ℃ for 3 hours under a vacuum condition.

5. The method of claim 1, wherein the laser printing is performed using a selective laser melting and forming device, comprising the steps of:

6. The method of claim 5, wherein the oxygen is removed to an oxygen concentration of less than 100ppm in the molding cavity.

7. The method according to claim 5, wherein the powder layer thickness is 25 μm/layer, the scan rate is 900mm/s, the scan angle is 67 °, and the scan path is in the form of stripes.

8. A zirconium based metallic glass produced by the method of any one of claims 1 to 7 wherein: the composition of the zirconium-based metallic glass is Zr₅₇Cu_15.4Ni_12.6Al₁₀Nb₅。