A high-density tungsten-refractory high-entropy alloy composite material and its preparation method

Abstract

This invention relates to the field of high-density tungsten alloy materials, specifically to a high-density tungsten-refractory high-entropy alloy composite material and its preparation method. The specific preparation method includes the following steps: using an iron-nickel phase as the binder phase and tungsten powder and refractory high-entropy alloy powder as the reinforcing phases, the tungsten powder, refractory high-entropy alloy powder, iron powder, and nickel powder are ball-milled and then subjected to spark plasma sintering at 1100℃~1300℃. During the sintering process, an iron-nickel phase and a reinforcing phase are formed, thus preparing the high-density tungsten-refractory high-entropy alloy composite material. This invention uses spark plasma sintering technology, and by changing the composition of the multi-principal tungsten alloy and the sintering process parameters, prepares various high-density tungsten-refractory high-entropy alloy composite materials with different compositions, microstructures, and mechanical properties, solving the problem of easy passivation of the projectile head during penetration in armor-piercing projectile core materials prepared from existing high-density tungsten alloy materials.

Description

Technical Field

[0001] This invention relates to the field of high-density tungsten alloy materials technology, specifically to a high-density tungsten-refractory high-entropy alloy composite material and its preparation method. Background Technology

[0002] Currently, tungsten alloys possess excellent properties such as high strength, high density, and good corrosion and oxidation resistance, making them widely used in the aerospace, military, and electronics industries. High-density tungsten alloys, in particular, can be used as core materials for armor-piercing projectiles in the military field.

[0003] High-density tungsten alloys are primarily based on tungsten, with small amounts of elements such as nickel, iron, and cobalt added to form a high-density two-phase alloy. For example, one currently researched high-density tungsten alloy material is mainly prepared by liquid-phase sintering of reduced tungsten powder, nickel powder, iron powder, and reduced cobalt powder. However, when these high-density tungsten alloy materials are used to prepare armor-piercing projectile core materials, they exhibit significant penetration resistance due to their adiabatic shear insensitivity. Because high-density tungsten alloys are thermally insensitive materials, they first undergo thermoplastic softening during high-speed penetration, resulting in a mushroom-shaped core head, followed by the appearance of an adiabatic shear band. Furthermore, the tungsten alloy is prone to passivation during penetration, thus substantially reducing its armor-piercing performance. Summary of the Invention

[0004] To address the problem of easy passivation of the projectile head during penetration by existing armor-piercing projectile core materials made of high-density tungsten alloys, the present invention aims to provide a high-density tungsten-refractory high-entropy alloy composite material and its preparation method.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows.

[0006] The first aspect of this invention provides a method for preparing a high-density tungsten-refractory high-entropy alloy composite material, comprising the following steps:

[0007] Using iron powder and nickel powder as binder phases, and tungsten powder and refractory high-entropy alloy powder as reinforcing phases, the tungsten powder, refractory high-entropy alloy powder, iron powder, and nickel powder were ball-milled and then subjected to spark plasma sintering at 1100℃~1300℃ to prepare a high-density tungsten-refractory high-entropy alloy composite material. The high-density tungsten-refractory high-entropy alloy composite material was prepared from the following raw materials by volume fraction:

[0008] Tungsten powder 62%–85%, refractory high-entropy alloy powder 10%–25%, and a mixture of iron and nickel powders 5%–20%, totaling 100%.

[0009] This invention primarily involves adjusting the ratio of the refractory high-entropy alloy reinforcing phase to the iron-nickel binder phase, combined with a spark plasma sintering process, to form both the iron-nickel phase and the reinforcing phase during sintering, thereby preparing a high-density tungsten-refractory high-entropy alloy composite material with excellent properties. This invention improves the density of the high-density tungsten-refractory high-entropy alloy composite material while simultaneously increasing its compressive strength and compressive strain, resulting in an actual density exceeding 15 g / cm³. 3 It has a density of over 98%, a compressive strength of nearly 2.5 GPa, and a compressive strain of over 25%.

[0010] Preferably, the refractory high-entropy alloy powder is composed of at least four elements selected from W, Mo, Ta, Nb, Hf, Zr, Ti, V, Fe, and Ni.

[0011] Preferably, the refractory high-entropy alloy powder is obtained by mixing powders of at least four elements selected from W, Mo, Ta, Nb, Hf, Zr, Ti, V, Fe, and Ni in an equimolar ratio, melting them into alloy button ingots by electric arc melting, hydrogenating and crushing the alloy button ingots, and then plasma spheroidizing them.

[0012] Preferably, the high-density tungsten-refractory high-entropy alloy composite material, by volume fraction, is prepared from the following raw materials:

[0013] Tungsten powder 62%–65%, refractory high-entropy alloy powder 15%–20%, and a mixture of iron and nickel powder 15%–20%, totaling 100%.

[0014] This invention helps to improve the density of high-density tungsten-refractory high-entropy alloy composite materials by adjusting the proportion of each raw material, especially adjusting the mixed powder of iron powder and nickel powder to within the range of 15% to 20%.

[0015] Preferably, the ball-to-material ratio in the ball milling mixture is 3 to 10:1. The ball-to-material ratio in the ball milling mixture can be adjusted according to the actual mixing situation.

[0016] Preferably, the ball milling speed is 200 r / min to 300 r / min, and the ball milling time is 8 h to 16 h. The ball milling speed and time can be adjusted according to the actual mixing situation.

[0017] Preferably, the sintering pressure of the spark plasma sintering is 5 MPa to 40 MPa.

[0018] Preferably, the sintering procedure of the discharge plasma sintering is as follows: under vacuum conditions, the temperature is increased to 1000°C at a heating rate of 100°C / min, then increased to 1100°C to 1300°C at a heating rate of 50°C / min, and then held at 1100°C to 1300°C for 5 min to 10 min.

[0019] Preferably, the sintering temperature of the discharge plasma sintering is 1200℃~1250℃.

[0020] This invention, by adjusting the sintering temperature of spark plasma sintering (SPCS), helps to study the influence of sintering temperature on the microstructure, mechanical properties, and sintering density of SPCS samples. Higher sintering temperatures increase the density of the sintered sample and improve the mechanical properties of the material; however, excessively high sintering temperatures can cause overflow during the sintering process. Similarly, lower sintering temperatures prevent the interstitial phase from completely melting during sintering, resulting in increased porosity in the sintered sample, reduced density, and consequently affecting the microstructure and mechanical properties of the sintered sample.

[0021] The second aspect of the present invention provides a high-density tungsten-refractory high-entropy alloy composite material, which is prepared by the preparation method described in the first aspect.

[0022] This invention utilizes spark plasma sintering to prepare various high-density tungsten-refractory high-entropy alloy composite materials with different compositions, microstructures, and mechanical properties by changing the composition of multi-principal tungsten alloys and sintering process parameters.

[0023] Preferably, the high-density tungsten-refractory high-entropy alloy composite material has a density of 96.8% to 99.3%, a compressive strength of 2501 MPa to 3050 MPa, and a compressive strain of 27% to 37%.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention uses spark plasma sintering technology to prepare a variety of high-density tungsten-refractory high-entropy alloy composite materials with different compositions, microstructures and mechanical properties by changing the composition of multi-principal tungsten alloys and sintering process parameters.

[0026] 2. The high-density tungsten-refractory high-entropy alloy composite material prepared by this invention has excellent mechanical properties, with an actual measured density exceeding 15 g / cm³. 3 The density can range from a minimum of 97% to a maximum of 99%. The compressive strength can exceed 3 GPa, and the compressive strain can reach over 35%.

[0027] 3. The preparation process of the present invention is simple to operate, the sintering time of the material is short, the molding effect is good, the material density is high, and it is easy to promote and apply. Attached Figure Description

[0028] Figure 1 This is a macroscopic image of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1.

[0029] Figure 2The image shows the microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1.

[0030] Figure 3 The compressive stress-strain curve of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1.

[0031] Figure 4 The image shows the microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 2.

[0032] Figure 5 The image shows the microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 3.

[0033] Figure 6 The compressive stress-strain curve of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 3.

[0034] Figure 7 The image shows the microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 4. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0036] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Currently, a high-density tungsten alloy material is being researched, mainly prepared by liquid-phase sintering of reduced tungsten powder, nickel powder, iron powder, and reduced cobalt powder. However, when this high-density tungsten alloy material is applied to the preparation of armor-piercing projectile core materials, it exhibits significant penetration resistance. Because the high-density tungsten alloy is an adiabatic shear-insensitive material, it first undergoes thermoplastic softening during high-speed penetration, forming a mushroom-shaped core head, before the appearance of an adiabatic shear band. Furthermore, the tungsten alloy is prone to passivation during penetration, thus substantially reducing its armor-piercing performance.

[0038] Refractory high-entropy alloys, as a type of multi-principal-element alloy, break through the traditional single-principal-element design concept of alloys, exhibiting superior properties unlike those of traditional alloys, especially showing promising application prospects in extreme environments such as high temperature, high pressure, and high strain rate. The emergence of high-entropy alloys has broken the traditional single-principal-element composition design concept based on mixing enthalpy. Multi-principal-element high-entropy alloys are characterized by high entropy values, severe lattice distortion, and hysteretic diffusion, which can promote the formation of simple solid solutions, thereby obtaining simple solid solution phases such as BCC, FCC, or HCP with excellent properties, or multiphase structures. They possess excellent comprehensive properties including high strength, high hardness, good plasticity, wear resistance, and corrosion resistance. Furthermore, due to their self-sharpening and energy release characteristics, they have broad application prospects in the military field.

[0039] Based on this, in order to solve the problem of easy passivation of the head of armor-piercing projectile core materials made of existing high-density tungsten alloy materials during penetration, this invention aims to combine refractory high-entropy alloys and high-density tungsten alloys, and use the properties of refractory high-entropy alloys to improve the problem of easy passivation of high-density tungsten alloys during penetration.

[0040] Spark plasma sintering (SPS) is an advanced materials processing technology primarily used in powder metallurgy. It combines the advantages of traditional hot pressing and electrical discharge machining (EDM) techniques, enabling the rapid and efficient direct sintering of metal or ceramic powders into dense solid materials. In SPS, the powder material is placed in a mold made of a conductive material, such as graphite. Two electrodes in contact with the mold apply pressure to the powder and pass a high-voltage pulsed current through it for a short time. The current passing through the powder generates resistance heating between the particles, resulting in localized high temperatures that promote particle bonding, ultimately forming a dense solid material. Because heating is concentrated at the particle contact points, the heating efficiency is extremely high. SPS offers a range of advantages, including rapid heating, short sintering time, controllable microstructure, energy efficiency, and environmental friendliness. These advantages compensate for the shortcomings of traditional powder metallurgy sintering techniques, providing an effective way to further improve the properties of tungsten alloys.

[0041] The technical solution of the present invention will be further described below through specific embodiments.

[0042] In the following embodiments, unless otherwise specified, the methods described are conventional methods; and unless otherwise specified, the reagents and materials described are commercially available.

[0043] Tungsten powder, specifications: 15-53μm / 1-3μm, Beijing Yanbang New Materials Technology Co., Ltd.

[0044] Iron powder, specifications: <10μm, Beijing Yanbang New Materials Technology Co., Ltd.

[0045] Nickel powder, specifications: <10μm, Beijing Yanbang New Materials Technology Co., Ltd.

[0046] WMoTaNb alloy powder, WMoTaNbTi alloy powder, WMoTaNbV alloy powder, specifications: 15μm~53μm, Beijing Yanbang New Materials Technology Co., Ltd.

[0047] WMoTaNb alloy powder is prepared by mixing W, Mo, Ta, and Nb in an equimolar ratio, melting them into WMoTaNb alloy button ingots using electric arc melting, hydrogenating and crushing the WMoTaNb alloy button ingots, and then plasma spheroidizing them.

[0048] WMoTaNbTi alloy powder is prepared by mixing W, Mo, Ta, Nb, and Ti in an equimolar ratio, melting them into WMoTaNbTi alloy button ingots using electric arc melting, hydrogenating and crushing the WMoTaNbTi alloy button ingots, and then plasma spheroidizing them.

[0049] WMoTaNbV alloy powder is prepared by mixing W, Mo, Ta, Nb, and V in an equimolar ratio, melting them into WMoTaNbV alloy button ingots using electric arc melting, hydrogenating and crushing the WMoTaNbV alloy button ingots, and then plasma spheroidizing them.

[0050] In the following embodiments, the mass ratio of iron powder to nickel powder is 1:2, and the volume ratio of iron powder to nickel powder is approximately 1:1.77. The volume ratio and volume fraction here are the volumes calculated after the components are fully densified.

[0051] Example 1

[0052] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0053] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of <10μm, nickel powder with a particle size of <10μm, and WMoTaNb alloy powder with a particle size of 15μm to 53μm.

[0054] Based on the volume fraction of tungsten powder (62%), iron and nickel powder (18%), and WMoTaNb alloy powder (20%), totaling 100%, the weight of each raw material was determined, and each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0055] Weigh all the raw materials and pour them into a 500mL nylon ball mill jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 3:1. Fix the nylon ball mill jar onto a planetary ball mill and ball mill at 300r / min for 8 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0056] Step 2, Sintering: Use a 42mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 80g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0057] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 30 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1200℃, and a holding time of 1200℃ for 10 minutes before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0058] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1 was used as sample 1 for photographing, microstructure observation and compressive stress-strain curve testing.

[0059] A photograph of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1 is shown below. Figure 1 As shown. The diameter of sample 1 was measured to be 42 mm. The density of sample 1, determined using Archimedes' displacement method, was 16.04 g / cm³. 3 The theoretical density is 16.2 g / cm³. 3 The calculated density of sample 1 was 99%.

[0060] The microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1 is as follows: Figure 2 As shown. By Figure 2 As can be seen, in the microstructure of sample 1, the white particles are tungsten particles, the spherical particles are WMoTaNb alloy powder, and the gray phase is FeNi phase.

[0061] The compressive stress-strain curve of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 1 is shown below. Figure 3 As shown. Two samples 1 were tested separately, and the average value of the test results was taken. Figure 3 It can be seen that sample 1 has a compressive strength of 2501 MPa and a compressive strain of 27%.

[0062] Example 2

[0063] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0064] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNbTi alloy powder with a particle size of 15μm to 53μm.

[0065] Based on the following formula: 62% tungsten powder, 18% iron and nickel powder, and 20% WMoTaNbTi alloy powder, totaling 100%, the weight of each raw material was determined, and each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0066] Weigh all the raw materials and pour them into a 500mL nylon ball mill jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 4:1. Fix the nylon ball mill jar onto a planetary ball mill and ball mill at 250r / min for 10 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0067] Step 2, Sintering: Use a 30mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 55g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0068] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 30 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1200℃, and a holding time of 1200℃ for 10 minutes before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0069] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 2 was used as sample 2 for photographing and microstructure observation.

[0070] The microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 2 is as follows: Figure 4 As shown. The diameter of sample 2 was measured to be 30 mm. The density of sample 2 was determined to be 98.5% according to Archimedes' displacement method. In the microstructure of sample 2, the white particles are tungsten particles, the spherical particles are WMoTaNbTi alloy powder, and the gray phase is FeNi phase.

[0071] Example 3

[0072] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0073] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 1μm to 3μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNbV alloy powder with a particle size of 15μm to 53μm.

[0074] Based on the following formula: 62% tungsten powder, 18% iron and nickel powder, and 20% WMoTaNbV alloy powder, totaling 100%, the weight of each raw material was determined, and each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0075] Weigh all the raw materials and pour them into a 500mL nylon ball mill jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 4:1. Fix the nylon ball mill jar onto a planetary ball mill and ball mill at 200r / min for 16 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0076] Step 2, Sintering: Use a 30mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 55g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0077] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 5 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1250℃, and a holding time of 10 minutes at 1250℃ before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0078] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 3 was used as sample 3, and photographs, microstructure observations and compressive stress-strain curve tests were performed.

[0079] The microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 3 is as follows: Figure 5 As shown. The diameter of sample 3 was measured to be 30 mm. The density of sample 3 was determined to be 97.9% according to Archimedes' displacement method. Figure 5As can be seen, in the microstructure of sample 3, the white particles are tungsten particles, the spherical particles are WMoTaNbV alloy powder, and the gray phase is FeNi phase.

[0080] The compressive stress-strain curve of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 3 is shown below. Figure 6 As shown. By Figure 6 It can be seen that sample 3 has a compressive strength of 3050 MPa and a compressive strain of 37%.

[0081] Example 4

[0082] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0083] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNbTi alloy powder with a particle size of 15μm to 53μm.

[0084] After determining the weight of each raw material according to the following formula: 70% by volume of tungsten powder, 10% by volume of iron and nickel powder, and 20% by volume of WMoTaNbTi alloy powder, totaling 100%, each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0085] Weigh all the raw materials and pour them into a 500mL nylon ball mill jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 4:1. Fix the nylon ball mill jar onto a planetary ball mill and ball mill at 250r / min for 10 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0086] Step 2, Sintering: Use a 30mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 55g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0087] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 40 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1200℃, and a holding time of 1200℃ for 10 minutes before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0088] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 4 was used as sample 4 for photographing and microstructure observation.

[0089] The diameter of sample 4 was measured to be 30 mm, and the density of sample 4 was only 87% according to Archimedes' displacement method.

[0090] The microstructure of the high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 4 is as follows: Figure 7 As shown. By Figure 7 As can be seen, the surface of sample 4 has many pores, which leads to low density. Compared with sample 2 of Example 2, it can be found that, under the same conditions, reducing the FeNi content can reduce the density of the high-density tungsten-refractory high-entropy alloy composite material.

[0091] Example 5

[0092] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0093] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNb alloy powder with a particle size of 15μm to 53μm.

[0094] After determining the weight of each raw material based on a volume fraction of 72% tungsten powder, 18% iron and nickel powder, and 10% WMoTaNb alloy powder (totaling 100%), each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0095] Weigh all the raw materials and pour them into a 500ml nylon ball milling jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 3:1. Fix the nylon ball milling jar onto a planetary ball mill and ball mill at 250r / min for 10 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0096] Step 2, Sintering: Use a 42mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 80g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0097] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 30 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1200℃, and a holding time of 1200℃ for 10 minutes before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0098] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 5 was used as sample 5, and the diameter of sample 5 was measured to be 42 mm. The density of sample 5 was determined to be 96.8% according to Archimedes' displacement method.

[0099] Example 6

[0100] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0101] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNb alloy powder with a particle size of 15μm to 53μm.

[0102] After determining the weight of each raw material based on a volume fraction of 85% tungsten powder, 5% iron and nickel powder, and 10% WMoTaNb alloy powder (totaling 100%), each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0103] Weigh all the raw materials and pour them into a 500ml nylon ball milling jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 3:1. Fix the nylon ball milling jar onto a planetary ball mill and ball mill at 250r / min for 10 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0104] Step 2, Sintering: Use a 42mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 80g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0105] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 30 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1250℃, and a holding time of 10 minutes at 1250℃ before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0106] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 6 was used as sample 6, and the diameter of sample 6 was measured to be 42 mm. The density of sample 6 was determined to be 72% according to Archimedes' displacement method.

[0107] Example 7

[0108] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0109] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNb alloy powder with a particle size of 15μm to 53μm.

[0110] After determining the weight of each raw material according to the following formula: 65% tungsten powder, 20% iron and nickel powder, and 15% WMoTaNb alloy powder, totaling 100%, each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0111] Weigh all the raw materials and pour them into a 500ml nylon ball milling jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 3:1. Fix the nylon ball milling jar onto a planetary ball mill and ball mill at 250r / min for 10 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0112] Step 2, Sintering: Use a 42mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 80g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0113] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 30 MPa. The sintering program was set as follows: a heating rate of 100°C / min from 0°C to 1000°C, a heating rate of 50°C / min from 1000°C to 1100°C, and a holding time of 1100°C for 10 minutes before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0114] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 7 was used as sample 7, and the diameter of sample 7 was measured to be 42 mm. The density of sample 7 was determined to be 99.3% according to Archimedes' displacement method.

[0115] Example 8

[0116] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0117] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNb alloy powder with a particle size of 15μm to 53μm.

[0118] After determining the weight of each raw material according to the following formula: 65% tungsten powder, 10% iron and nickel powder, and 25% WMoTaNb alloy powder, totaling 100%, each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0119] Weigh all the raw materials and pour them into a 500ml nylon ball milling jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 3:1. Fix the nylon ball milling jar onto a planetary ball mill and ball mill at 250r / min for 10 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0120] Step 2, Sintering: Use a 42mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 80g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0121] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 30 MPa. The sintering program was set as follows: a heating rate of 100°C / min from 0°C to 1000°C, a heating rate of 50°C / min from 1000°C to 1300°C, and a holding time of 1300°C for 10 minutes before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0122] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 8 was used as sample 8, and the diameter of sample 8 was measured to be 42 mm. The density of sample 8 was determined to be 88.1% according to Archimedes' displacement method.

[0123] Example 9

[0124] A method for preparing a high-density tungsten-refractory high-entropy alloy composite material includes the following steps:

[0125] Step 1, Preparation of mixed powder for sintering: First, design the composition of high specific gravity tungsten-refractory high entropy alloy composite material, using tungsten powder with a particle size of 15μm to 53μm, iron powder with a particle size of less than 10μm, nickel powder with a particle size of less than 10μm, and WMoTaNbV alloy powder with a particle size of 15μm to 53μm.

[0126] Based on the following formula: 62% tungsten powder, 18% iron and nickel powder, and 20% WMoTaNbV alloy powder, totaling 100%, the weight of each raw material was determined, and each raw material was weighed. The purity of each raw material used was ≥99.9%.

[0127] Weigh all the raw materials and pour them into a 500mL nylon ball mill jar. According to the total weight of the raw materials, add the corresponding weight of zirconia grinding balls at a ball-to-material ratio of 4:1. Fix the nylon ball mill jar onto a planetary ball mill and ball mill at 200r / min for 16 hours. After ball milling, use a sieve to sift out the ball-milled mixed powder to obtain the mixed powder for sintering.

[0128] Step 2, Sintering: Use a 30mm diameter graphite mold as the sintering mold, and spray a high-temperature boron nitride release agent onto the mold head and inner wall. Pour 55g of sintering mixed powder into the graphite mold; wrap carbon paper around the contact surface between the sintering mixed powder and the graphite mold, and wrap the outside of the graphite mold with carbon felt to improve the heat preservation effect of the graphite mold.

[0129] A graphite mold containing the mixed powder for sintering was placed in a spark plasma sintering furnace. Afterward, a vacuum was applied for 15 minutes, followed by a pressure of 5 MPa. The sintering program was set as follows: a heating rate of 100℃ / min from 0℃ to 1000℃, a heating rate of 50℃ / min from 1000℃ to 1250℃, and a holding time of 10 minutes at 1250℃ before sintering began. After sintering, the furnace was cooled, the furnace door was opened, samples were taken, and the mold was removed to obtain a high-density tungsten-refractory high-entropy alloy composite material.

[0130] The high-density tungsten-refractory high-entropy alloy composite material prepared by sintering in Example 9 was used as sample 9, and the diameter of sample 9 was measured to be 30 mm. The density of sample 9 was determined to be 97.5% according to Archimedes' displacement method. Sample 9 was found to have a compressive strength of 2845 MPa and a compressive strain of 24.1%.

[0131] The high-density tungsten-refractory high-entropy alloy composite materials prepared by sintering in Examples 1 to 9 were used as samples 1, 2, 3, 4, 5, 6, 7, 8, and 9, respectively. The comparison of the amount of raw materials used to prepare samples 1 to 9 is shown in Table 1. The comparison of the particle size of the raw materials used to prepare samples 1 to 9 is shown in Table 2.

[0132] Table 1 Comparison of the amount of raw materials used in the preparation of samples 1 to 9

[0133]

[0134]

[0135] Table 2 Comparison of particle size of raw materials used to prepare samples 1 to 8

[0136] Example tungsten powder Iron powder and nickel powder Refractory high-entropy alloy powder Sample Example 1 15μm~53μm <10μm 15μm~53μm Sample 1 Example 2 15μm~53μm <10μm 15μm~53μm Sample 2 Example 3 1μm~3μm <10μm 15μm~53μm Sample 3 Example 4 15μm~53μm <10μm 15μm~53μm Sample 4 Example 5 15μm~53μm <10μm 15μm~53μm Sample 5 Example 6 15μm~53μm <10μm 15μm~53μm Sample 6 Example 7 15μm~53μm <10μm 15μm~53μm Sample 7 Example 8 15μm~53μm <10μm 15μm~53μm Sample 8 Example 9 15μm~53μm <10μm 15μm~53μm Sample 9

[0137] Note: The refractory high-entropy alloy powder of samples 1 and 5-8 is WMoTaNb alloy powder; the refractory high-entropy alloy powder of samples 2 and 4 is WMoTaNbTi alloy powder; the refractory high-entropy alloy powder of samples 3 and 9 is WMoTaNbV alloy powder.

[0138] Density calculations and mechanical property tests were performed on samples 1 to 9, and the results are shown in Table 3.

[0139] Table 3. Test results of density and mechanical properties of samples 1 to 8

[0140] Sample diameter Density compressive strength Compressive strain Sample 1 42mm 99％ 2501MPa 27％ Sample 2 30mm 98.5％ 2931MPa 21％ Sample 3 30mm 97.9％ 3050MPa 37％ Sample 4 30mm 87％ 2447MPa 12％ Sample 5 42mm 96.8％ 2200MPa 22％ Sample 6 42mm 72％ 1822MPa 9％ Sample 7 42mm 99.3％ 2213MPa 31％ Sample 8 42mm 88.1％ 2203MPa 13％ Sample 9 30mm 97.5％ 2845MPa 24.1％

[0141] Note: "-" indicates that it has not been tested.

[0142] Analysis of Tables 1-3 shows that the density of the samples decreases significantly with decreasing iron and nickel powder content. Specifically, when the volume fraction of iron and nickel powder is 15%–20%, the density of the samples is above 96%; when the volume fraction of iron and nickel powder is 10%, the density of the samples is 87%–88.1%; and when the volume fraction of iron and nickel powder is less than 10%, the density of the samples is 72%. This demonstrates that the content of iron and nickel powder can affect the density of the prepared samples.

[0143] Refractory high-entropy alloy powder, as a reinforcing phase of composite materials, directly affects the strength of the sample. As can be seen from the comparison between Example 1 and Example 5, under the same conditions, the increased WMoTaNb content leads to increased compressive strength and decreased compressive strain in the sample.

[0144] A comparison of Examples 1 and 9 shows that, under the same conditions, the compressive strength and compressive strain increase with decreasing tungsten powder particle size. This demonstrates that the particle size of tungsten powder can affect the mechanical properties of the prepared samples.

[0145] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-density tungsten-refractory high-entropy alloy composite material, characterized in that, Includes the following steps: Using iron powder and nickel powder as the binder phase and tungsten powder and refractory high-entropy alloy powder as the reinforcing phase, the tungsten powder, refractory high-entropy alloy powder, iron powder and nickel powder are ball-milled and then subjected to spark plasma sintering at 1100℃~1300℃ for 5min~10min. During the sintering process, iron-nickel phase and reinforcing phase are formed, thus preparing a high-density tungsten-refractory high-entropy alloy composite material. The high-density tungsten-refractory high-entropy alloy composite material, by volume fraction, is prepared from the following raw materials: Tungsten powder 62%–65%, refractory high-entropy alloy powder 15%–20%, mixed powder of iron and nickel powder 15%–20%, totaling 100%; The refractory high-entropy alloy powder is composed of at least four elements selected from W, Mo, Ta, Nb, Hf, Zr, Ti, V, Fe, and Ni.

2. The method for preparing the high-density tungsten-refractory high-entropy alloy composite material according to claim 1, characterized in that, The refractory high-entropy alloy powder is obtained by mixing powders of at least four elements selected from W, Mo, Ta, Nb, Hf, Zr, Ti, V, Fe, and Ni in an equimolar ratio, melting them into alloy button ingots by electric arc melting, hydrogenating and crushing the alloy button ingots, and then plasma spheroidizing them.

3. The method for preparing the high-density tungsten-refractory high-entropy alloy composite material according to claim 1, characterized in that, The ball-to-material ratio for ball milling is 3 to 10:

1.

4. The method for preparing the high-density tungsten-refractory high-entropy alloy composite material according to claim 1, characterized in that, The ball milling speed is 200 r / min to 300 r / min, and the ball milling time is 8 h to 16 h.

5. The method for preparing the high-density tungsten-refractory high-entropy alloy composite material according to claim 1, characterized in that, The sintering pressure of the discharge plasma sintering is 5 MPa to 40 MPa.

6. The method for preparing the high-density tungsten-refractory high-entropy alloy composite material according to claim 1, characterized in that, The sintering procedure of the discharge plasma sintering is as follows: under vacuum conditions, the temperature is increased to 1000℃ at a heating rate of 100℃ / min, then increased to 1100℃~1300℃ at a heating rate of 50℃ / min, and then held at 1100℃~1300℃ for 5min~10min.

7. A high-density tungsten-refractory high-entropy alloy composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 6.

8. The high-density tungsten-refractory high-entropy alloy composite material according to claim 7, characterized in that, The high-density tungsten-refractory high-entropy alloy composite material has a density of 96.8% to 99.3%, a compressive strength of 2501 MPa to 3050 MPa, and a compressive strain of 27% to 37%.

Images