Method for improving performance of high-entropy alloy-aluminum-based composite material through cooperation of high-temperature oxidation and ball milling

Abstract

The invention belongs to the technical field of metal-based composite materials, and particularly discloses a method for cooperatively improving the performance of a high-entropy alloy-aluminum-based composite material through high-temperature oxidation-ball milling. Firstly, high-temperature heat treatment is conducted on high-entropy alloy powder, the phase type, size and distribution of the high-entropy alloy powder are regulated and controlled, the intrinsic mechanical property of the high-entropy alloy powder is remarkably improved, then the high-entropy alloy powder subjected to heat treatment is further treated through a ball milling technology, nano-particles distributed on the surface in a dispersed mode are formed, and therefore the effect of the high-entropy alloy powder serving as a reinforcement phase is enhanced; uniformly mixing the modified high-entropy alloy powder with aluminum alloy powder, and preparing a high-performance aluminum-based composite material by adopting a spark plasma sintering technology; results show that the method disclosed by the invention obviously improves the tensile strength and the ductility of the composite material, and realizes synergistic enhancement of obdurability; the method provides a new thought and technical means for preparing the high-performance metal-based composite material, and has important theoretical significance and practical application value.

Description

Technical Field

[0001] The invention belongs to the technical field of metal-based composite materials, and specifically discloses a method for synergistically improving the performance of a high-entropy alloy-aluminum-based composite material by high-temperature oxidation-ball milling. Background Art

[0002] Aluminum-based composites have high specific strength, high specific stiffness, good wear resistance and fatigue resistance, excellent dimensional stability, electrical conductivity and thermal conductivity, and are widely used in aerospace, national defense, military, transportation and other fields. There has been extensive research on the design and preparation of particle-reinforced aluminum-based composites. Traditional reinforcement phases mainly involve traditional metal materials such as ceramic materials, carbon materials, steel and titanium. The wettability of the interface between ceramic and aluminum matrix is ​​poor, and the thermal expansion coefficients of the two are very different. In particular, the intrinsic brittle characteristics of ceramic materials lead to high strength and poor plasticity of ceramic-reinforced aluminum-based composites. The thermal expansion coefficient of carbon materials is quite different from that of aluminum alloys, and microcracks are easily generated at the interface. Due to the good interface bonding characteristics between metal and metal, metal particles or metal fibers are introduced into the metal matrix as a reinforcement phase to prepare metal-based composites with excellent performance. High entropy alloys have excellent strength and toughness properties and are considered to be the preferred materials to replace traditional steel, titanium, nickel and other metals as reinforcement phases. Therefore, it is expected to improve the strength-toughness mismatch problem of traditional aluminum-based composites by reinforcing and toughening aluminum alloys with high entropy alloys.

[0003] Peng et al. used spark plasma sintering (SPS) technology to prepare 3 vol% CoCrFeNi high entropy alloy (HEA) reinforced 6061Al matrix composites, and proposed a new strategy to regulate the interface structure of the diffusion layer by solution heat treatment (Peng Xiao, Qiqiang Zhao, et al. Interface characteristics and tensile fracture behavior of CoCrFeNi / 6061Al matrix composites fabricated via spark plasmasintering and heat treatment. [J]. Materials Characterization. 208 (2024) 113685). A uniform diffusion layer is formed between HEA and the Al matrix, and the thickness of the diffusion layer increases with the extension of the solution time. The diffusion layer is a double-layer structure, with columnar crystals near HEA and equiaxed crystals along the Al9Co2 solid solution layer near the Al matrix. When the solution time is 60 min and the thickness is 12.8 μm, the tensile strength and elongation of the alloy are 211.5 MPa and 21.4%, respectively. Qiang et al. prepared Al with a volume fraction of 10% by vacuum hot pressing sintering. 0.6CoCrFeNi high entropy alloy particle reinforced titanium matrix composite (Fei Qiang, Shewei Xin., et al. Formation mechanism of interdiffusion layerand mechanical properties of Al0.6CoCrFeNi high-entropy alloy / Ti composites[J]. Journal of Alloys and Compounds 943(2023)169151). An interdiffusion layer consisting of AlNi2Ti (BCC) and Ni-Ti mixed phase (FCC) is formed between the HEA particles and the matrix. Smith Salifu et al. used SPS technology to prepare high entropy alloy reinforced aluminum matrix composites (using 5, 7 and 10wt% HEA as reinforcement, respectively). Al-rich regions and HEA element-rich regions were formed at the interface, and nano-precipitated phases were formed during the sintering process (Smith Salifu, Peter Apata Olubambi..Microstructural and nanoindentation study of spark plasmasintered high entropy alloy reinforced aluminium matrix composites[J].Journal of Alloys and Compounds 999(2024)175021).

[0004] Current research shows that good interface bonding between HEA particles and the matrix can significantly improve the strength and hardness of the composite material. Cheng Buyun et al. found that the addition of HEA particles to aluminum-based composites increased the microhardness by 69%, and further enhanced the mechanical properties of the material through grain refinement and dislocation strengthening mechanisms (Cheng Buyun, Zhang Hongxia, Yang Xiao, et al. Research on the modification and performance of high entropy alloy stir friction processing on aluminum alloy surface [J]. Journal of Taiyuan University of Technology, 2021, 52(03): 397-403). Peng Yanzhi et al. developed a CrMnFeCoNi high entropy alloy particle reinforced aluminum-based composite with a "dual-metal" heterogeneous structure (Yangzhi Peng,. Caiju li, Min Song, et al. Breaking the strength-ductility trade-off in aluminum matrix composite through "dual-metal" heterogeneous structure and interface control. [J]. International Journal of Plasticity, 185(2025)104216). The double-shell structure and multi-layer heterogeneous interface design of HEA particles can effectively accommodate deformation, reduce stress concentration and inhibit crack propagation, thereby achieving a good synergy of strength and plasticity.

[0005] However, the performance of composite materials is still insufficient, especially in terms of plasticity and corrosion resistance. Peng Haokai et al. found that when the aluminum-based composite material has a high content of reinforcing phase, the interfacial brittle phase will increase, resulting in a decrease in plastic deformation capacity (Peng Haokai, Liu Yao, Ma Donglin, et al. Research progress on interface regulation and plastic deformation behavior of B4Cp / Al composite materials [J]. Composite Materials Science and Engineering, 2023, (04): 128-136). Wei Yiyun et al. found that the corrosion resistance of composite materials in a corrosive environment is also affected by the interface structure and needs to be further optimized (Wei Yiyun. Preparation, mechanical and corrosion properties of MgZnCa-based amorphous and its composite materials [D]. Chongqing University, 2012).

[0006] Specifically, although some studies have been conducted to improve the performance of high entropy alloy reinforced aluminum-based composites by regulating the interface structure of the diffusion layer through solution heat treatment and forming an interdiffusion layer, the overall performance of the composites, especially the plasticity and corrosion resistance, still needs to be improved. In addition, the existing technology for processing high entropy alloy powders is relatively single, and it is difficult to simultaneously achieve the improvement of the intrinsic performance of the high entropy alloy reinforcement phase and the strengthening of its interface with the aluminum matrix. Summary of the invention

[0007] In order to solve the above problems, the present invention discloses a method for synergistically improving the performance of a high-entropy alloy-aluminum-based composite material by high-temperature oxidation-ball milling. The high-entropy alloy powder is first preheated and oxidized, and then the heat-treated high-entropy alloy powder is ball-milled. The internal and surface characteristic structures of the high-entropy alloy are synergistically regulated by the thermal oxidation treatment and the ball milling process. Subsequently, the synergistically modified high-entropy alloy powder is mixed with an aluminum alloy powder and sintered using the spark plasma sintering technology SPS to prepare an aluminum-based composite material with improved strength and plasticity, thereby providing a novel method for the preparation of high-performance metal-based composite materials.

[0008] The present invention includes the following technical solutions:

[0009] A method for synergistically improving the performance of a high entropy alloy-aluminum-based composite material by high-temperature oxidation-ball milling, comprising the following steps:

[0010] a) heat treatment step: heat treating the high entropy alloy powder at 900-1200° C., wherein the heat treatment comprises first keeping the powder in an argon atmosphere for 5-15 hours, then keeping the powder in an oxygen atmosphere for 2-8 hours, then stopping heating and cooling the powder to room temperature with the furnace, to obtain a heat-treated reinforcement phase powder;

[0011] b) ball milling step: ball milling the heat-treated high entropy alloy powder obtained in step a), with a ball milling speed of 150 rpm-450 rpm, a ball-to-material ratio of 5:1 to 20:1, and a ball milling time of 5-20 h to obtain a modified high entropy alloy powder;

[0012] c) powder mixing step: mixing the modified high entropy alloy powder obtained in step b) with the aluminum alloy powder, with a ball milling speed of 80-100 rpm, a ball-to-material ratio of 3:1, and a ball milling time of 10-60 min to obtain a mixed powder;

[0013] d) Sintering and molding step: Sintering and molding step: The mixed powder obtained in step c) is sintered by spark plasma sintering technology SPS to prepare a high entropy alloy-aluminum-based composite material.

[0014] Preferably, in the above SPS step, the mixed powder is placed in a mold with a diameter of 70 mm, heated to 600° C., kept warm for 30 minutes, and the uniaxial pressure is 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0015] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, the high-entropy alloy is AlCoCrFeNi high-entropy alloy.

[0016] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, the aluminum alloy is a 2xxx series aluminum alloy.

[0017] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, in the step a) heat treatment step, the heat treatment temperature is 1100°C, and it is kept in an argon atmosphere for 10 hours and then kept in an oxygen atmosphere for 5 hours.

[0018] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, in the step b) of ball milling treatment, the ball milling speed is 150rpm-450rpm, the ball-to-material ratio is 5:1 to 20:1, and the ball milling time is 5-20h.

[0019] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling to synergistically improve the performance of high-entropy alloy-aluminum-based composite materials, in the step b) of ball milling treatment, the ball milling speed is 300 rpm, the ball-to-material ratio is specifically 5:1, and the ball milling time is 5 hours.

[0020] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling to synergistically improve the performance of high-entropy alloy-aluminum-based composite materials, in the step c) of mixing powders, the ball milling speed is 80-100 rpm, the ball-to-material ratio is 3:1, and the ball milling time is 10-60 min.

[0021] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, in the step c) of mixing powders, the volume ratio of high-entropy alloy powder to aluminum alloy powder is 5-15:95.

[0022] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, in the step c) of mixing powders, the volume ratio of high-entropy alloy powder to aluminum alloy powder is 5:95.

[0023] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, in the step c) of mixing powders, the average particle size of the high-entropy alloy powder is 10 μm.

[0024] Furthermore, in the above-mentioned method of high-temperature oxidation-ball milling synergistically improving the performance of high-entropy alloy-aluminum-based composite materials, in the step c) of mixing powders, the aluminum alloy is 2024Al.

[0025] The present invention also discloses an aluminum-based composite material, which is prepared by any of the above methods. The composite material has a tensile strength of not less than 318.4 MPa and an elongation of not less than 12.3%.

[0026] Compared with the prior art, the present invention has the following outstanding beneficial effects:

[0027] (1) After the high-entropy alloy powder is treated in a high-temperature oxidizing atmosphere and an inert atmosphere, on the one hand, the microstructure of the high-entropy alloy phase type, size, distribution, etc. is regulated, and the intrinsic mechanical properties of the high-entropy alloy powder can be improved. For example, most of the existing studies use single-phase high-entropy alloy powder to reinforce metal-based composite materials, which will lead to serious mismatches in the strength, toughness and other properties of the composite materials; on the other hand, oxygen doping, vacancy distribution, oxide and other amorphous phase distribution can be formed on the surface of the high-entropy alloy powder, which is beneficial to improve the interface element diffusion, interface layer thickness, and interface reaction products at the interface between the high-entropy alloy and the metal matrix during the subsequent sintering process, thereby helping to regulate the performance of the metal-based composite material. Therefore, in this patent, high-temperature heat treatment can not only improve the intrinsic microstructure and intrinsic properties of the high-entropy alloy powder, but also achieve doping and modification of the surface interface.

[0028] (2) Experiments have shown that the combination of high-temperature heat treatment and subsequent ball milling can significantly improve the performance of the final composite material. The ball milling process after high-temperature treatment will further affect the surface structure of the high-entropy alloy and introduce a certain degree of deformation energy, which affects the interface reaction between the high-entropy alloy and the metal matrix during the subsequent sintering process.

[0029] In short, by combining the high-temperature heat treatment process and ball milling process of the high-entropy alloy, the intrinsic performance of the high-entropy alloy reinforcement phase is improved, and the bonding strength of the interface between the high-entropy alloy and the metal matrix is ​​achieved, and finally the synergistic improvement of the strength and toughness of the aluminum-based composite material is achieved. This is the biggest innovation. The performance of general composite materials is strength improvement, but the plasticity is significantly reduced, and the aluminum-based composite material of the present invention has successfully broken this conventional limitation. By finely regulating the microstructure and surface properties of the high-entropy alloy, and optimizing its interface bonding with the metal matrix, we have not only achieved a significant improvement in strength, but more importantly, the plasticity has also been effectively maintained or even improved. This breakthrough is undoubtedly a major innovation in the field of composite materials.

[0030] Furthermore, the preparation method of the present invention has high controllability and repeatability, and can ensure that each batch of composite materials can achieve the expected performance indicators. This not only provides strong technical support for industrial production, but also opens up a new path for the application of aluminum-based composite materials in a wider range of fields.

[0031] In summary, the present invention not only improves the intrinsic performance of the high-entropy alloy reinforcement phase by combining the high-temperature heat treatment process with the ball milling process, but also enhances the interfacial bonding strength between the high-entropy alloy reinforcement phase and the metal matrix, and finally achieves a synergistic improvement in the strength and toughness of the aluminum-based composite material. This innovative achievement not only has significant scientific value, but also has important practical application significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The change of tensile stress-strain curve of the composite material under the synergistic influence of high-entropy alloy powder high-temperature heat treatment and ball milling process. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Figure 1 The corresponding Table 1 is as follows:

[0035] Table 1: Figure 1 The tensile mechanical properties of the corresponding composite materials

[0036]

[0037] Experimental materials and instruments:

[0038] The AlCoCrFeNi high entropy alloy in step 1) has an equiatomic composition ratio and is prepared by the research team through atomization powder making.

[0039] High energy ball mill, model MAX1600, with stainless steel grinding balls of 8 mm in diameter.

[0040] The aluminum alloy powder is 2 series spherical 2024 aluminum alloy with an average particle size of 20 μm.

[0041] Example 1

[0042] High temperature treatment, ball milling, 300rpm-5:1

[0043] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder with a particle size of 10 μm was selected as the reinforcement phase. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h.

[0044] (2) Ball milling of high-entropy alloy powders subjected to high-temperature heat treatment: A high-energy ball mill was used for ball milling, with a ball milling speed of 300 rpm, a ball-to-material ratio of 5:1, and a ball milling time of 5 h.

[0045] (3) Preparation of composite materials: A ball mill was used to mix high entropy alloy powder and aluminum alloy powder. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, the ball milling time was 30 min, and the volume ratio of high entropy alloy powder to aluminum alloy powder was 5:95.

[0046] (4) Preparing a composite material using SPS; sintering the mixed powder obtained in step c) using spark plasma sintering technology (SPS), placing the mixed powder in a mold with a diameter of 70 mm, heating to 600° C., keeping warm for 30 min, and applying a uniaxial pressure of 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0047] After the uniaxial tensile test at room temperature, the tensile strength of the aluminum-based composite material of this embodiment is 318.4 MPa and the elongation is 12.3%. Figure 1 The blue curve shows.

[0048] Example 2

[0049] High temperature treatment, ball milling, 450rpm-5:1

[0050] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder with a particle size of 10 μm was selected as the reinforcement phase. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h.

[0051] (2) Ball milling of high-entropy alloy powders subjected to high-temperature heat treatment: A high-energy ball mill was used for the ball milling process. The ball milling speed was 450 rpm, the ball-to-material ratio was 5:1, and the total ball milling time was 5 h.

[0052] (3) Preparation of composite materials: A ball mill was used to mix high entropy alloy powder and aluminum alloy powder. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, the ball milling time was 30 min, and the volume ratio of high entropy alloy powder to aluminum alloy powder was 5:95.

[0053] (4) Preparation of composite materials using SPS: The mixed powder obtained in step c) is sintered using spark plasma sintering technology (SPS), the mixed powder is placed in a mold with a diameter of 70 mm, heated to 600°C, and kept warm for 30 minutes. The uniaxial pressure is 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0054] After the room temperature uniaxial tensile test, the tensile strength of the aluminum-based composite material of this embodiment is 334.0 MPa and the elongation is 9.9%. Figure 1 The green curve is shown.

[0055] Example 3

[0056] High temperature treatment, ball milling, 150rpm-10:1

[0057] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder was selected as the reinforcement phase, with an average particle size of 10 μm. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h;

[0058] (2) Ball milling of high-entropy alloy powders subjected to high-temperature heat treatment: A high-energy ball mill was used for the ball milling process, with a ball milling speed of 150 rpm, a ball-to-material ratio of 10:1, and a ball milling time of 5 h.

[0059] (3) Preparation of composite materials: A ball mill was used to mix high entropy alloy powder and aluminum alloy powder. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, the ball milling time was 30 min, and the volume ratio of high entropy alloy powder to aluminum alloy powder was 5:95.

[0060] (4) Preparation of composite materials using SPS: The mixed powder obtained in step c) is sintered using spark plasma sintering technology (SPS), the mixed powder is placed in a mold with a diameter of 70 mm, heated to 600°C, and kept warm for 30 minutes. The uniaxial pressure is 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0061] After the room temperature uniaxial tensile test, the tensile strength of the high entropy alloy reinforced aluminum-based composite material of this embodiment is 326.0 MPa, and the elongation is 10.8%. Figure 1 Shown as the purple curve.

[0062] Example 4

[0063] High temperature treatment, ball milling, 150rpm-20:1

[0064] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder was selected as the reinforcement phase, with an average particle size of 10 μm. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h;

[0065] (2) Ball milling of high-entropy alloy powders subjected to high-temperature heat treatment: A high-energy ball mill was used for the ball milling process, with a ball milling speed of 150 rpm, a ball-to-material ratio of 20:1, and a ball milling time of 5 h.

[0066] (3) Preparation of composite materials: A ball mill was used to mix high entropy alloy powder and aluminum alloy powder. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, and the ball milling time was 30 min. The volume ratio of high entropy alloy powder to aluminum alloy powder was 5:95.

[0067] (4) Preparation of composite materials using SPS: The mixed powder obtained in step c) is sintered using spark plasma sintering technology (SPS), the mixed powder is placed in a mold with a diameter of 70 mm, heated to 600°C, and kept warm for 30 minutes. The uniaxial pressure is 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0068] After the uniaxial tensile test at room temperature, the tensile strength of the aluminum-based composite material of this embodiment is 323.4 MPa, and the elongation is 12.0%. Figure 1 The yellow curve shows

[0069] Comparative Example 1

[0070] Not high temperature treated, not ball milled

[0071] (1) Powder mixing: The original high entropy alloy powder that has not been heat treated and ball-milled is directly mixed with the aluminum alloy powder, the ball milling speed is 90 rpm, the ball-to-material ratio is 3:1, the ball milling time is 30 min, and the volume ratio of the high entropy alloy powder to the aluminum alloy powder is 5:95 to obtain a mixed powder;

[0072] (2) Preparation of composite materials: The composite materials were prepared by SPS. The mixed powder obtained in step 1) was sintered using spark plasma sintering technology (SPS). The mixed powder was placed in a mold with a diameter of 70 mm, heated to 600°C, and kept warm for 30 min. The uniaxial pressure was 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0073] After the room temperature uniaxial tensile test, the ultimate tensile strength of the original high entropy alloy reinforced aluminum matrix composite material of this comparative example is 275.7MPa, and the elongation is 8.7%. Figure 1 The red curve shows

[0074] Comparative Example 2

[0075] High temperature treatment, not ball milled

[0076] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder with a particle size of 10 μm was selected as the reinforcement phase. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h.

[0077] (2) Preparation of composite materials: High entropy alloy powders that were heat treated at high temperature were directly mixed with aluminum alloy powders using a ball mill. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, the ball milling time was 30 min, and the volume ratio of high entropy alloy powder to aluminum alloy powder was 5:95.

[0078] (3) Using SPS to prepare a composite material from the mixed powder; sintering the mixed powder obtained in step 2) using spark plasma sintering technology (SPS), placing the mixed powder in a mold with a diameter of 70 mm, heating to 600°C, keeping warm for 30 minutes, and applying a uniaxial pressure of 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0079] After the room temperature uniaxial tensile test, the aluminum-based composite material of this comparative example has a tensile strength of 297.7 MPa and an elongation of 15.6%. Figure 1 The black curve is shown.

[0080] It can be seen from the test results of Examples 1 to 4 and two comparative examples that the high entropy alloy powder treated with different ball milling process parameters and high-temperature heat treatment can significantly affect the mechanical properties of the aluminum-based composite material.

[0081] Specifically, it can be seen from Table 1 that all composite materials prepared from high-entropy alloy powders that have been subjected to high-temperature heat treatment (regardless of whether they have been ball-milled) have better tensile strength and elongation than the composite materials prepared from the original high-entropy alloy powders that have not been subjected to high-temperature heat treatment (Comparative Example 1). This shows that high-temperature heat treatment has a significant effect on improving the performance of composite materials.

[0082] Further comparison found that the composite material (Example 1 to Example 4) prepared from the high-temperature heat-treated high-entropy alloy powder after ball milling has different degrees of improvement in tensile strength compared with the composite material (Comparative Example 2) that has only been subjected to high-temperature heat treatment but not ball milled. At the same time, the difference in ball milling process parameters also leads to differences in the elongation of the composite material. In the embodiment, the changes in ball milling speed and ball-to-material ratio have an impact on the tensile strength and elongation of the composite material, among which Example 2 (ball milling speed 450rpm, ball-to-material ratio 5:1) has the highest tensile strength, reaching 334.0MPa, but the elongation is relatively low; and Example 4 (ball milling speed 150rpm, ball-to-material ratio 20:1) has the highest elongation, which is 12.0%.

[0083] The following conclusions can be drawn from the above embodiments and comparative examples:

[0084] High-temperature heat treatment has a significant effect on improving the performance of composite materials: regardless of whether ball milling treatment is performed or not, the performance of composite materials prepared from high-entropy alloy powders that have undergone high-temperature heat treatment is better than that of composite materials that have not undergone high-temperature heat treatment.

[0085] Ball milling can further improve the performance of composite materials: Based on high-temperature heat treatment, the tensile strength of composite materials can be further improved by ball milling, but the change in elongation depends on the selection of ball milling process parameters.

[0086] The selection of ball milling process parameters has a significant impact on the performance of composite materials: different ball milling speeds and ball-to-material ratios will lead to different changes in the tensile strength and elongation of the composite materials, which need to be optimized according to specific needs.

[0087] In summary, the present invention successfully prepared an aluminum-based composite material with excellent performance by combining high-temperature heat treatment with ball milling process and optimizing ball milling process parameters, providing new ideas and technical means for the preparation of high-performance metal-based composite materials.

[0088] Example 5

[0089] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder with a particle size of 10 μm was selected as the reinforcement phase. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h.

[0090] (2) Ball milling of high-entropy alloy powders subjected to high-temperature heat treatment: A high-energy ball mill was used for ball milling, with a ball milling speed of 300 rpm, a ball-to-material ratio of 5:1, and a ball milling time of 5 h.

[0091] (3) Preparation of composite materials: A ball mill was used to mix high entropy alloy powder and aluminum alloy powder. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, the ball milling time was 30 min, and the volume ratio of high entropy alloy powder to aluminum alloy powder was 15:95.

[0092] (4) Preparing a composite material using SPS; sintering the mixed powder obtained in step c) using spark plasma sintering technology (SPS), placing the mixed powder in a mold with a diameter of 70 mm, heating to 600° C., keeping warm for 30 min, and applying a uniaxial pressure of 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0093] Example 6

[0094] (1) High-temperature heat treatment of high-entropy alloy powder: AlCoCrFeNi high-entropy alloy powder with a particle size of 10 μm was selected as the reinforcement phase. The high-entropy alloy powder was kept at 1100°C in an argon atmosphere for 10 h and in an oxygen atmosphere for 5 h.

[0095] (2) Ball milling of high-entropy alloy powders subjected to high-temperature heat treatment: A high-energy ball mill was used for ball milling, with a ball milling speed of 300 rpm, a ball-to-material ratio of 5:1, and a ball milling time of 5 h.

[0096] (3) Preparation of composite materials: A ball mill was used to mix high entropy alloy powder and aluminum alloy powder. The ball milling speed was 90 rpm, the ball-to-material ratio was 3:1, the ball milling time was 30 min, and the volume ratio of high entropy alloy powder to aluminum alloy powder was 10:95.

[0097] (4) Preparing a composite material using SPS; sintering the mixed powder obtained in step c) using spark plasma sintering technology (SPS), placing the mixed powder in a mold with a diameter of 70 mm, heating to 600° C., keeping warm for 30 min, and applying a uniaxial pressure of 50 MPa to prepare a high entropy alloy-aluminum-based composite material.

[0098] The above are only a few preferred embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for synergistically improving the performance of high entropy alloy-aluminum-based composite materials by high temperature oxidation-ball milling, characterized in that: The following steps are involved: a) heat treatment step: heat treating the high entropy alloy powder at 900-1200° C., wherein the heat treatment comprises first keeping the powder in an argon atmosphere for 5-15 hours, then keeping the powder in an oxygen atmosphere for 2-8 hours, then stopping heating and cooling the powder to room temperature with the furnace, to obtain a heat-treated reinforcement phase powder; b) ball milling step: ball milling the heat-treated high entropy alloy powder obtained in step a) to obtain a modified high entropy alloy powder; c) a powder mixing step: mixing the modified high entropy alloy powder obtained in step b) with the aluminum alloy powder to obtain a mixed powder; d) Sintering molding step: The mixed powder obtained in step c) is sintered by spark plasma sintering technology SPS to prepare a high entropy alloy-aluminum-based composite material.

2. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: The high entropy alloy is AlCoCrFeNi high entropy alloy.

3. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: The aluminum alloy is a 2xxx series aluminum alloy.

4. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: In the step a) of heat treatment, the heat treatment temperature is 1100° C., and the heat treatment is carried out under an argon atmosphere for 10 hours and then under an oxygen atmosphere for 5 hours.

5. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: In the step b) of ball milling, the ball milling speed is 150 rpm-450 rpm, the ball-to-material ratio is 5:1 to 20:1, and the ball milling time is 5-20 h.

6. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: In the step c) of mixing powder, the ball milling speed is 80-100 rpm, the ball-to-material ratio is 3:1, and the ball milling time is 10-60 min.

7. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: In the step c) of mixing powders, the volume ratio of the high entropy alloy powder to the aluminum alloy powder is 5-15:

95.

8. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: In the step c) of mixing powders, the average particle size of the high entropy alloy powder is 10 μm.

9. The method of high temperature oxidation-ball milling synergistically improving the performance of high entropy alloy-aluminum-based composite materials according to claim 1, characterized in that: In the step c) of mixing powder, the aluminum alloy is 2024Al.

10. An aluminum-based composite material, characterized in that: The composite material is prepared by the method according to any one of claims 1 to 9, and has a tensile strength of not less than 318.4 MPa and an elongation of not less than 12.3%.

Images