An aluminum tungsten-based gradient composite material and a method for preparing the same

Abstract

The application belongs to the technical field of metal matrix composite material preparation, and provides an aluminum-tungsten-based gradient composite material and a preparation method thereof.The method of the application comprises the following steps: after tungsten powder and aluminum powder are mixed according to different mass percentages, the mixed powder is ball-milled under the protection of argon gas to obtain six groups of mixed powder; then, cold pressing forming and sequential stacking are performed to form a laminated structure; after the laminated structure is compacted, explosion sintering is performed under emulsion explosive; and the sintered product is heat treated to obtain the aluminum-tungsten-based gradient composite material.The method of the application significantly improves the density and mechanical properties of the Al-W-based gradient composite material.The Al-W powder with different proportions is cold-pressed and laminated to form, and then explosion sintering is performed to complete the densification of the gradient structure.The method of the application can efficiently prepare large-size Al-W-based gradient composite materials with different density distributions, and can be applied to the field of high-end equipment manufacturing, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of metal matrix composite material preparation, and in particular to an aluminum-tungsten-based gradient composite material and a preparation method thereof. Background Art

[0002] With the continuous advancement of science and technology in recent years, high-end equipment and scientific fields such as national defense and security have received significant development attention. These fields often face complex loading environments. Consequently, material requirements are constantly increasing, and various alloys are being used in high-end equipment manufacturing. Among them, aluminum-tungsten gradient materials (Al-W gradient materials) possess unique material properties. Composed of two phases of aluminum and tungsten, they are functional gradient materials that combine the characteristics of both metals. Elemental aluminum metal exhibits excellent ductility, electrical and thermal conductivity, while elemental tungsten metal possesses high hardness, a high melting point, and relatively stable chemical properties. The addition of tungsten to Al-W gradient materials significantly enhances the material's strength and hardness. Due to tungsten's extremely high melting point, Al-W alloys maintain excellent stability under high-temperature and high-pressure environments, resisting deformation or melting. This gives Al-W gradient materials significant advantages in high-end manufacturing.

[0003] Al-W gradient materials have the characteristics of large differences in density and melting point. During the preparation process of Al-W gradient materials, a variety of aluminum-tungsten intermetallic compounds (Al-W) are easily generated at the Al-W interface, which are unstable under high pressure and easy to phase change. 12 W, Al5W, Al4W, etc.), which makes the mechanical properties of Al-W gradient materials relatively poor, and it is impossible to completely fuse the properties of the two into one. In recent years, domestic and foreign scholars have conducted a lot of research on the preparation of Al-W-based metal gradient materials. The most common methods for preparing Al-W-based metal gradient materials in the early days were powder hot isostatic pressing and cold isostatic pressing. The mechanical properties of Al-W-based gradient materials prepared by this method are poor, and they are only bonded by weak surface diffusion. Their compressive strength is less than 150MPa, and the interface shows brittle fracture, which will eventually lead to cracking when preparing large-scale gradient materials. In recent years, the most common method for preparing Al-W-based gradient materials is the non-equilibrium preparation method, which includes mechanical alloying and solution method. The non-equilibrium preparation process mainly occurs in the powder pre-treatment process, while non-equilibrium preparation processes such as large plastic deformation, magnetron sputtering, and laser selective melting occur in the densification process.

[0004] In the non-equilibrium preparation method, the densification sintering temperature is high, which leads to the Al content in the Al-W based gradient material. 12Excessive content of intermetallic compounds such as W, Al5W, and Al4W results in poor toughness and low strength, making them susceptible to defects such as holes and cracks. Alternatively, when the strength is high, the tungsten content in the Al-W-based gradient material is too low (<50%), making it impossible to obtain Al-W-based composite materials with high tungsten content. Currently, conventional preparation methods are unable to control the melting point difference and phase formation between aluminum and tungsten materials. There is an urgent need to develop new preparation methods to obtain Al-W-based gradient materials with high density, excellent mechanical properties, and controllable phases.

[0005] Currently, among the patents related to Al-W-based composite materials, patent number CN 105908020 B discloses a method for preparing an aluminum-tungsten composite material. In this patent, semi-solid casting technology and mechanical stirring methods are used to prepare the Al-W-based composite material. This method contains relatively more elements other than Al-W, resulting in a low purity of the Al-W-based composite material. The low W content cannot form a gradient composite material, and therefore it is difficult to ensure the strength and toughness of the Al-W-based composite material. Patent number CN 102703768 B discloses an aluminum-tungsten composite material and a preparation method thereof. In this patent, aluminum plates and tungsten metal particles are used as raw materials, and the aluminum-tungsten composite material is prepared by cumulative roll-bonding. In this method, a large amount of intermetallic compounds are present, and the low W content cannot form a gradient composite material.

[0006] Therefore, it is of great significance to provide a method for regulating the melting point difference and phase generation between Al-W based gradient materials to prepare aluminum-tungsten based gradient composite materials with excellent mechanical properties and high density. Summary of the Invention

[0007] The purpose of the present invention is to provide an aluminum-tungsten-based gradient composite material and a preparation method thereof in order to overcome the deficiencies of the prior art. The aluminum-tungsten-based gradient composite material of the present invention has excellent mechanical properties and high density.

[0008] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0009] The present invention provides a method for preparing an aluminum-tungsten-based gradient composite material, comprising the following steps:

[0010] 1) Tungsten powder and aluminum powder were mixed in different mass percentages and then ball-milled under argon protection to obtain six groups of mixed powders;

[0011] 2) The six groups of mixed powders are cold pressed to obtain six groups of composite material blanks;

[0012] 3) Stacking six groups of composite material blanks from bottom to top in order of tungsten content from low to high to form a laminated structure;

[0013] 4) After the laminated structure is compacted, explosive sintering is performed under emulsion explosives to obtain a sintered product;

[0014] 5) The sintered product is heat treated to obtain an aluminum-tungsten based gradient composite material.

[0015] Preferably, the mass percentage of Al powder in the first group of mixed powders is 0%, and the mass percentage of W powder is 100%; the mass percentage of Al powder in the second group of mixed powders is 18-22%, and the mass percentage of W powder is 78-82%; the mass percentage of Al powder in the third group of mixed powders is 38-42%, and the mass percentage of W powder is 58-62%; the mass percentage of Al powder in the fourth group of mixed powders is 58-62%, and the mass percentage of W powder is 38-42%; the mass percentage of Al powder in the fifth group of mixed powders is 78-82%, and the mass percentage of W powder is 18-22%; and the mass percentage of Al powder in the sixth group of mixed powders is 100%, and the mass percentage of W powder is 0%.

[0016] Preferably, the ball milling time in step 1) is 1.5-2.5 h; and the particle sizes of the tungsten powder and the aluminum powder are independently 2-20 μm.

[0017] Preferably, the pressure of the cold pressing in step 2) is 280-320 MPa.

[0018] Preferably, the mixed powders corresponding to the six groups of composite material blanks stacked sequentially from bottom to top in step 3) are the sixth group of mixed powders, the fifth group of mixed powders, the fourth group of mixed powders, the third group of mixed powders, the second group of mixed powders, and the first group of mixed powders.

[0019] Preferably, the compaction pressure in step 4) is 90-110 MPa.

[0020] Preferably, the explosive sintering time in step 4) is 1-10 ms, and the explosive sintering pressure is 5-30 GPa.

[0021] Preferably, the temperature of the heat treatment in step 5) is 300-600° C., and the heat treatment time is ≥30 min.

[0022] The present invention also provides an aluminum-tungsten-based gradient composite material prepared by the preparation method of the aluminum-tungsten-based gradient composite material.

[0023] The beneficial effects of the present invention include the following:

[0024] 1) This invention provides a method for preparing an aluminum-tungsten gradient composite material through a powder layering method and explosive sintering. This method significantly improves the density and mechanical properties of the Al-W gradient composite material. Al-W powders of varying proportions are cold-pressed and laminated, followed by explosive sintering to achieve densification of the gradient structure. The explosive sintering method features a short sintering time, low sintering temperature, and high sintering pressure that increases layer by layer, effectively reducing the formation of intermetallic compounds, preserving the properties of the raw materials, and significantly improving the material's strength and toughness.

[0025] 2) The present invention prepares large-scale Al-W-based gradient materials with accurate density distribution by regulating the melting point difference and phase generation between Al-W-based gradient materials and stacking Al-W-based gradient materials with different densities. When the Al-W-based gradient material is prepared by explosive sintering, the amount of intermetallic compounds generated is small, which is conducive to maintaining the high toughness of Al and the high strength characteristics of W. The explosive sintering time is extremely short, and due to the density and composition differences between different layers, the explosion shock wave forms a different pressure distribution in each layer, so that the material is densified layer by layer. Vacuum heat treatment can optimize the microstructure of the Al-W-based composite material, reduce the formation of microcracks and pores, and promote material densification through heat treatment to further enhance the strength and toughness of the Al-W-based gradient composite material.

[0026] 3) The method of the present invention can efficiently prepare large-sized Al-W-based gradient composite materials with different density distributions, which can be applied in the field of high-end equipment manufacturing and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of sealing of explosive sintering mold of the present invention;

[0028] Figure 2 The relationship between W content and pressure when preparing aluminum-tungsten gradient composites for different types of explosives. DETAILED DESCRIPTION

[0029] The present invention provides a method for preparing an aluminum-tungsten-based gradient composite material, comprising the following steps:

[0030] 1) Tungsten powder and aluminum powder were mixed in different mass percentages and then ball-milled under argon protection to obtain six groups of mixed powders;

[0031] 2) The six groups of mixed powders are cold pressed to obtain six groups of composite material blanks;

[0032] 3) Stacking six groups of composite material blanks from bottom to top in order of tungsten content from low to high to form a laminated structure;

[0033] 4) After the laminated structure is compacted, explosive sintering is performed under emulsion explosives to obtain a sintered product;

[0034] 5) The sintered product is heat treated to obtain an aluminum-tungsten based gradient composite material.

[0035] In the present invention, the mass percentage of Al powder in the first group of mixed powders is 0%, and the mass percentage of W powder is 100%; the mass percentage of Al powder in the second group of mixed powders is preferably 18-22%, more preferably 19-21%, more preferably 20%, and the mass percentage of W powder is preferably 78-82%, more preferably 79-81%, more preferably 80%; the mass percentage of Al powder in the third group of mixed powders is preferably 38-42%, more preferably 39-41%, more preferably 40%, and the mass percentage of W powder is preferably 58-62%, more preferably 59-61%, more preferably 6 0%; the mass percentage of Al powder in the fourth group of mixed powders is preferably 58-62%, more preferably 59-61%, more preferably 60%, and the mass percentage of W powder is preferably 38-42%, more preferably 39-41%, more preferably 40%; the mass percentage of Al powder in the fifth group of mixed powders is preferably 78-82%, more preferably 79-81%, more preferably 80%, and the mass percentage of W powder is preferably 18-22%, more preferably 19-21%, more preferably 20%; the mass percentage of Al powder in the sixth group of mixed powders is 100%, and the mass percentage of W powder is 0%.

[0036] In the present invention, the ball milling time in step 1) is preferably 1.5-2.5 h, more preferably 1.8-2.2 h, and more preferably 2 h; the particle sizes of the tungsten powder and aluminum powder are independently preferably 2-20 μm, more preferably 2 μm, 10 μm, and 20 μm.

[0037] In the present invention, pure argon is filled in the process of ball milling the mixing materials in step 1) to prevent the powder from being oxidized.

[0038] In the present invention, the pressure of the cold pressing in step 2) is preferably 280-320 MPa, more preferably 290-310 MPa, and even more preferably 300 MPa; the cold pressing is preferably performed in a tablet press, and the cold pressing can increase the initial density of the rough blank.

[0039] In the present invention, the mixed powders corresponding to the six groups of composite material blanks stacked from bottom to top in step 3) are preferably the sixth group of mixed powder, the fifth group of mixed powder, the fourth group of mixed powder, the third group of mixed powder, the second group of mixed powder, and the first group of mixed powder.

[0040] In the present invention, the compaction pressure in step 4) is preferably 90-110 MPa, more preferably 95-105 MPa, and even more preferably 100 MPa.

[0041] In the present invention, the time of the explosive sintering in step 4) is preferably 1-10 ms, more preferably 3-8 ms, and even more preferably 5-6 ms, and the pressure of the explosive sintering is preferably 5-30 GPa.

[0042] The sealing diagram of the explosive sintering mold of the present invention is as follows Figure 1 As shown, the gradient structure can be densified under the promotion of explosion pressure.

[0043] In the present invention, during the explosive sintering process, the pressure of each layer increases gradually from the bottom to the top to achieve effective sintering of different layers of Al-W-based composite materials, thereby preparing a high-strength and tough Al-W-based gradient composite material; the explosive sintering is carried out in a polyvinyl chloride tube (PVC tube), and the explosive sintering achieves dense sintering of the Al-W-based composite material.

[0044] The melting points of aluminum and tungsten differ significantly. Sintering becomes more difficult with higher tungsten content in Al-W composites, and the explosive sintering pressure increases significantly with increasing tungsten content. Consequently, the explosive sintering pressures of Al-W composite rough sheets with varying compositions and porosities vary significantly. The explosive shockwave acts on the Al-W stack rough sheets in a mold, explosively sintering them in a very short time. Due to the varying density and composition of the different layers, the explosive shockwave creates a different pressure distribution within each layer.

[0045] The present invention adopts an explosion method to prepare an aluminum-tungsten based gradient composite material, and the explosion method is also a type of non-equilibrium method. The Al-W based gradient composite material is obtained by explosive sintering, and then the microstructure of the Al-W based gradient composite material is regulated by heat treatment. During the conduction of the explosion shock wave, the explosion sintering pressure of each layer is different, resulting in the pressure gradually increasing with the density during the preparation of the Al-W based gradient material. This feature is suitable for the preparation of densified, high-tungsten content Al-W based gradient composite materials with different density distributions. When the Al-W based gradient composite material is prepared by the explosion method, a wavy interface is easily generated between laminated materials of different densities, but the wave width is small. The organizational structure of the Al-W based gradient composite material can be precisely regulated by adjusting the explosion parameters and the heat treatment process parameters.

[0046] In the present invention, the temperature of the heat treatment in step 5) is preferably 300-600°C, more preferably 350-550°C, more preferably 400-500°C, and the heat treatment time is preferably ≥30 min, more preferably ≥35 min, more preferably ≥40 min.

[0047] The present invention also provides an aluminum-tungsten-based gradient composite material prepared by the preparation method of the aluminum-tungsten-based gradient composite material.

[0048] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0049] In the embodiment, Al powder is prepared by mixing Al powder with a particle size of 2 μm, Al powder with a particle size of 10 μm, and Al powder with a particle size of 20 μm in a mass ratio of 3:2:1; W powder is prepared by mixing W powder with a particle size of 2 μm, W powder with a particle size of 10 μm, and W powder with a particle size of 20 μm in a mass ratio of 1:2:3.

[0050] Example 1

[0051] Tungsten powder and aluminum powder were mixed at varying mass percentages to produce six groups of powders. Each of the six groups of powders was placed in a ball mill and milled at 200 rpm under a pure argon atmosphere for 2 hours to ensure uniform mixing of the Al-W powders. The first group of mixed powders contained 0% Al powder and 100% W powder; the second group contained 20% Al powder and 80% W powder; the third group contained 40% Al powder and 60% W powder; the fourth group contained 60% Al powder and 40% W powder; the fifth group contained 80% Al powder and 20% W powder; and the sixth group contained 100% Al powder and 0% W powder.

[0052] The six groups of mixed powders were placed separately in a tablet press and cold-pressed at 300 MPa for 5 minutes to form six groups of composite rough sheets of varying densities. These rough sheets were then layered, in ascending order of tungsten content (the sixth, fifth, fourth, third, second, and first groups, all of equal mass), into an explosively sintered ultra-high-strength steel mold to form a multi-layered structure.

[0053] The mold containing the multi-layered laminate is sealed and compacted in a tablet press at a pressure of 100 MPa to ensure close contact between each rough layer and the mold. The mold containing the compacted laminate is then placed in a 110 mm outer diameter PVC pipe filled with No. 42 rock emulsion explosive. The PVC pipe is filled with a 300 mm charge of No. 42 rock emulsion explosive, ensuring explosive sintering for 5 ms. The explosive is detonated from a safe distance, and the shock wave from the explosion sinters the Al-W rough laminate in the mold. Due to the differences in density and composition of the different layers, the shock wave creates a different pressure distribution in each layer (the explosion creates a pressure gradient that increases from 5 to 25 GPa layer by layer, overcoming the sintering barriers of the gradient material layer), leading to layer-by-layer densification of the material.

[0054] After the explosive sintering is completed, the sintered material is placed in a vacuum furnace for heat treatment with a vacuum degree of 0.1 Pa, a heat treatment temperature of 500°C, and a heat treatment time of 35 min to obtain an aluminum-tungsten based gradient composite material.

[0055] Example 2

[0056] Tungsten powder and aluminum powder were mixed at varying mass percentages to produce six groups of powders. Each of the six groups of powders was placed in a ball mill and milled at 200 rpm under a pure argon atmosphere for 2.5 hours to ensure uniform mixing of the Al-W powders. The first group of mixed powders contained 0% Al powder and 100% W powder; the second group contained 20% Al powder and 80% W powder; the third group contained 40% Al powder and 60% W powder; the fourth group contained 60% Al powder and 40% W powder; the fifth group contained 80% Al powder and 20% W powder; and the sixth group contained 100% Al powder and 0% W powder.

[0057] The six groups of mixed powders were placed separately in a tablet press and cold-pressed at 310 MPa for 5 minutes to form six composite rough sheets of varying densities. These rough sheets were then layered, in ascending order of tungsten content (the sixth, fifth, fourth, third, second, and first groups, all of equal mass), into an explosively sintered ultra-high-strength steel mold to form a multi-layered structure.

[0058] The mold containing the multi-layered laminate is sealed and compacted in a tablet press at 95 MPa to ensure close contact between each rough layer and the mold. The mold containing the compacted laminate is placed in a 110 mm outer diameter PVC pipe, which is filled with No. 42 rock emulsion explosive. A 320 mm high column of No. 42 rock emulsion explosive is placed in the PVC pipe. A layer of sodium polyacrylate hydrogel is applied to the seal, ensuring explosive sintering time of 8 ms. The explosive is detonated from a safe distance, and the shock wave from the explosion sinters the Al-W laminate rough layer in the mold. Due to the differences in density and composition of the different layers, the shock wave creates a different pressure distribution in each layer (the explosion creates a pressure gradient that increases layer by layer from 6 to 28 GPa upwards, overcoming the sintering barriers of the gradient material layer), resulting in layer-by-layer densification of the material.

[0059] After the explosive sintering is completed, the sintered material is placed in a vacuum furnace for heat treatment with a vacuum degree of 0.1 Pa, a heat treatment temperature of 400°C, and a heat treatment time of 40 min to obtain an aluminum-tungsten based gradient composite material.

[0060] Example 3

[0061] The six sets of composite material blanks forming the multilayered structure in Example 1 were modified to have a mass ratio of 1:1.2:1.4:1.6:1.8:2 for each layer from bottom to top, forming an Al-W-based gradient composite material with increasing density layer by layer. Other process parameters remained the same as in Example 1, resulting in a higher-strength, more uniform gradient composite material.

[0062] The aluminum-tungsten based gradient composite material of this embodiment further improves the density and mechanical properties of the gradient composite material.

[0063] Example 4

[0064] During explosive sintering, the laminated materials of different compositions form a wavy interface structure under pressure. By adjusting the charge height and a small amount of filler based on Example 1, while maintaining the same other process parameters as in Example 1, a higher strength, more uniform gradient composite material can be obtained.

[0065] Comparative Example 1

[0066] The No. 42 rock emulsion explosive in Example 1 was replaced by TNT and ammonia oil explosive respectively, and other conditions were the same as in Example 1.

[0067] The relationship between W content and pressure when preparing aluminum-tungsten gradient composite materials with different types of explosives is shown in the figure below. Figure 2As shown in the figure, in the Al-W based gradient composite material, the tungsten content of each layer gradually decreases from the top to the bottom, and the temperature difference required to densify each layer is very large. The first layer is pure tungsten powder (melting point is 3410℃), and the sixth layer is pure aluminum powder (melting point is 660℃). In a uniform thermal field, a very large temperature gradient is required to achieve densification of each layer of the Al-W based gradient composite material, and pure liquid phase sintering cannot be used because the tungsten particles will settle during the sintering process and the gradient effect cannot be achieved. Figure 2 In order to utilize the gradient pressure generated during explosive sintering to replace the difficult-to-achieve temperature gradient, gradient pressure is used to weaken the physical property differences of the sintering barriers between different layers of gradient materials. Figure 2 The pressure gradient formed inside the aluminum-tungsten gradient composite material when preparing aluminum-tungsten gradient composite materials for different types of explosives and when preparing aluminum-tungsten gradient composite materials by non-explosive sintering.

[0068] This invention applies the explosive method to the preparation of Al-W-based gradient composite materials. By controlling the pressure required during explosive sintering of each layer of Al-W rough stock, the result is minimal or no diffusion at the particle interfaces during explosive sintering of the Al-W-based gradient composite material. This minimizes the formation of intermetallic compounds, helps maintain the good properties of the raw materials, and addresses the problem of excessive intermetallic compound content that often occurs in non-equilibrium preparation methods. The present invention features a short sintering time, low overall sintering temperature, and high sintering pressure (in the GPa range), with the pressure gradually increasing with the density of the sintered material.

[0069] The preparation method of the present invention realizes the integrated preparation of Al-W based gradient composite materials with different compositions and density distributions through layered powder laying and explosive sintering processes. The aluminum-tungsten based gradient composite materials have good strength, toughness and density, and greatly reduce the amount of intermetallic compounds generated.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an aluminum-tungsten based gradient composite material, characterized in that: The following steps are included: 1) Tungsten powder and aluminum powder were mixed in different mass percentages and then ball-milled under argon protection to obtain six groups of mixed powders; 2) The six groups of mixed powders are respectively cold pressed to obtain six groups of composite material blanks; 3) stacking six groups of composite material blanks from bottom to top in order of tungsten content from low to high to form a laminated structure; 4) After the laminated structure is compacted, explosive sintering is performed under emulsion explosives to obtain a sintered product; 5) heat treating the sintered product to obtain an aluminum-tungsten based gradient composite material; The mass percentage of Al powder in the first group of mixed powders is 0%, and the mass percentage of W powder is 100%; The mass percentage of Al powder in the second group of mixed powders is 18-22%, and the mass percentage of W powder is 78-82%; The mass percentage of Al powder in the third group of mixed powders is 38-42%, and the mass percentage of W powder is 58-62%; The mass percentage of Al powder in the fourth group of mixed powders is 58-62%, and the mass percentage of W powder is 38-42%; The mass percentage of Al powder in the fifth group of mixed powders is 78-82%, and the mass percentage of W powder is 18-22%; The mass percentage of Al powder in the sixth group of mixed powders is 100%, and the mass percentage of W powder is 0%.

2. The method for preparing the aluminum-tungsten based gradient composite material according to claim 1, characterized in that: In step 1), the ball milling time is 1.5 to 2.5 hours; the particle sizes of the tungsten powder and the aluminum powder are independently 2 to 20 μm.

3. The method for preparing the aluminum-tungsten based gradient composite material according to claim 2, characterized in that: Step 2) The pressure of the cold pressing molding is 280-320 MPa.

4. The method for preparing the aluminum-tungsten based gradient composite material according to claim 3, characterized in that: Step 3) The mixed powders corresponding to the six groups of composite material blanks stacked from bottom to top are the sixth group of mixed powder, the fifth group of mixed powder, the fourth group of mixed powder, the third group of mixed powder, the second group of mixed powder, and the first group of mixed powder.

5. The method for preparing the aluminum-tungsten based gradient composite material according to claim 4, characterized in that: The compaction pressure in step 4) is 90-110 MPa.

6. The method for preparing the aluminum-tungsten based gradient composite material according to claim 4 or 5, characterized in that: Step 4) The time of the explosive sintering is 1 to 10 ms, and the pressure of the explosive sintering is 5 to 30 GPa.

7. The method for preparing the aluminum-tungsten based gradient composite material according to claim 6, characterized in that: Step 5) The heat treatment temperature is 300-600° C., and the heat treatment time is ≥30 min.

8. The aluminum-tungsten based gradient composite material prepared by the method for preparing the aluminum-tungsten based gradient composite material according to any one of claims 1 to 7.

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