Aluminum-based entropy alloy and preparation method and application thereof

Abstract

The invention discloses an aluminum-based entropy alloy and a preparation method and application thereof. The chemical formula of the aluminum-based entropy alloy is Al < x > Si < y > Mg < z > Cu Zn < v >, and in the formula, the molar percentage of subscript corresponding element atoms is x + y + z + u + v = 100, x = 78-82, y = 7.2-8.8, z = 3.6-4.4, u = 3.6-4.4, and v = 3.6-4.4. The preparation method of the aluminum-based entropy alloy comprises the following steps: 1) smelting; 2) refining and degassing; (3) vacuum die casting; and 4) heat treatment. The aluminum-based entropy alloy has the advantages of high strength, high plasticity, low production cost, simple preparation process and the like, can be used in the fields of aerospace, automobile industry, ocean engineering and the like, particularly in high-temperature scenes requiring light weight and high strength, and is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to an aluminum-based entropy alloy and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of the aerospace and automotive industries and the increasing requirements for environmental protection and energy conservation and emission reduction, people have put forward higher requirements for the mechanical properties of aluminum alloy die castings in extreme environments (for example: high strength, heat resistance and corrosion resistance, etc.). High entropy alloys, also known as multi-component alloys, have the characteristics of high strength, high fracture toughness, good corrosion resistance and good high temperature stability, and have become a research hotspot in recent years. Moreover, with the continuous development of high entropy alloys, the research on entropy alloys has gradually expanded to medium entropy alloys and low entropy alloys, and the emergence of entropy alloys has also provided new strategies and ideas for the design of traditional aluminum alloys.

[0003] At present, the preparation method of aluminum-based entropy alloy is mainly casting, but the casting method has a slow filling speed, and defects such as looseness, shrinkage, inclusions, and insufficient pouring are prone to occur in the alloy, which will eventually lead to low plasticity (<10%) of the prepared aluminum-based entropy alloy. In recent years, some researchers have begun to use additive manufacturing and high temperature and high pressure methods to prepare aluminum-based entropy alloys. Due to the layer-by-layer stacking characteristics of additive manufacturing, the prepared parts usually have various phases, poor uniformity, and poor surface quality, and this method is not suitable for the preparation of large-sized and complex-shaped parts. High temperature and high pressure technology has high requirements for equipment and high costs, and is not suitable for mass production. In summary, the existing preparation process of aluminum-based entropy alloys needs to be improved, and the performance of aluminum-based entropy alloys is still difficult to fully meet the requirements of practical applications, and needs to be further improved.

[0004] Therefore, it is of great significance to develop an aluminum-based entropy alloy with high strength, high plasticity, low production cost and simple preparation process. Summary of the invention

[0005] The purpose of the present invention is to provide an aluminum-based entropy alloy and a preparation method and application thereof.

[0006] The technical solution adopted by the present invention is:

[0007] An aluminum-based entropy alloy, the chemical formula of which is Al x Si y Mg z Cu u Zn v , where the subscripts correspond to the molar percentage of element atoms, x+y+z+u+v=100, x=78~82, y=7.2~8.8, z=3.6~4.4, u=3.6~4.4, v=3.6~4.4.

[0008] Preferably, the aluminum-based entropy alloy is made of the following raw materials in percentage by mass:

[0009] Pure aluminum: 24.10% to 36.64%;

[0010] Al-Si20 master alloy: 34.10%~40.85%;

[0011] Al-Mg50 master alloy: 5.90%~7.06%;

[0012] Al-Cu50 master alloy: 15.42%~18.48%;

[0013] Pure zinc: 7.94%~9.51%.

[0014] Preferably, the purity of the pure aluminum is ≥99.80%.

[0015] Preferably, the purity of the Al-Si20 master alloy, the Al-Mg50 master alloy and the Al-Cu50 master alloy is ≥99.90%.

[0016] Preferably, the purity of the pure zinc is ≥99.00%.

[0017] A method for preparing the aluminum-based entropy alloy as described above comprises the following steps:

[0018] 1) Melting: Dry the prepared raw materials, add them into a melting furnace for melting, and obtain a melt;

[0019] 2) Refining and degassing: adding a refining agent to the melt for refining, and then degassing, standing and removing impurities to obtain refined aluminum liquid;

[0020] 3) Die casting: inject refined aluminum liquid into the mold for vacuum die casting to obtain aluminum-based entropy alloy die castings;

[0021] 4) Heat treatment: subjecting the aluminum-based entropy alloy die casting to solid solution treatment and aging treatment to obtain the aluminum-based entropy alloy.

[0022] Preferably, the smelting in step 1) includes the following operations: adding pure aluminum into a smelting furnace, gradually heating up to 695°C-705°C, and waiting for the aluminum ingot to be completely melted. Then, sequentially adding Al-Si20 master alloy and Al-Cu50 master alloy, stirring for 15min-25min after the alloy is completely melted, cooling to 645°C-655°C, and then adding Al-Mg50 master alloy preheated to 170°C-190°C and pure zinc preheated to 170°C-190°C, and keeping the alloy and pure zinc warm for 15min-25min after the alloy and pure zinc are completely melted.

[0023] Preferably, the refining agent in step 2) is the rare earth multifunctional aluminum alloy slag removal refining agent ZS-AJ01c produced by Foshan Nanhai Lvyuan Metal Supporting Materials Co., Ltd.

[0024] Preferably, the amount of the refining agent in step 2) is 0.3% to 0.5% of the mass of the melt.

[0025] Preferably, the refining in step 2) is carried out at a temperature of 645°C to 655°C.

[0026] Preferably, the refining and degassing in step 2) comprises the following operations: adding a refining agent to the melt, skimming off the scum after refining for 15 to 25 minutes, then introducing high-purity argon gas for degassing, standing for 15 to 25 minutes, and then removing the slag on the surface of the melt.

[0027] Preferably, the vacuum die-casting in step 3) is carried out under the condition of vacuum degree ≤ 100 mbar.

[0028] Preferably, the solution treatment in step 4) is carried out at a temperature of 445° C. to 455° C., and the treatment time is 0.5 h to 3 h.

[0029] Preferably, the solution treatment in step 4) is followed by water quenching at room temperature (25°C±5°C).

[0030] Preferably, the aging treatment in step 4) is carried out at room temperature for a treatment time of 12 h to 24 h.

[0031] An application of the aluminum-based entropy alloy as described above in the aerospace field, the automotive industry field or the marine engineering field.

[0032] The beneficial effects of the present invention are: the aluminum-based entropy alloy of the present invention has the advantages of high strength, high plasticity, low production cost, simple preparation process, etc., and can be used in aerospace, automotive industry, marine engineering and other fields, especially in high-temperature scenarios requiring lightweight and high strength, and is suitable for large-scale industrial production and application.

[0033] Specifically:

[0034] 1) The cast room temperature compressive strength of the aluminum-based entropy alloy of the present invention can reach 816MPa, the yield strength can reach 538MPa, the fracture plasticity can reach 19.3%, and the density is about 2.85g / cm 3 After heat treatment, the room temperature compressive strength can reach 896MPa~919MPa, the yield strength can reach 555MPa~566MPa, and the fracture plasticity can reach 25.4%~27.0%. Not only is the strength higher than that of existing traditional aluminum alloys, aluminum-based entropy alloys and additively manufactured aluminum alloys, but the density is also lower. This is of great significance for broadening the application scope of aluminum alloys, and the practical application prospects are very broad;

[0035] 2) The aluminum-based entropy alloy of the present invention has a high Si content, good fluidity, does not contain high-cost alloying elements such as rare earth, Mo, Sc, and Ti, and has a low production cost;

[0036] 3) The aluminum-based entropy alloy of the present invention has few hole defects, and the mechanical properties of the alloy can be further improved through solution treatment and aging treatment;

[0037] 4) The present invention prepares aluminum-based entropy alloys by vacuum die-casting, eliminating defects such as looseness, shrinkage cavities, inclusions, and insufficient pouring that are easily produced by existing casting methods, greatly improving the mechanical properties, surface quality and uniformity of the aluminum-based entropy alloys, achieving a good match between strength and plasticity, and being suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the XRD diagram of the aluminum-based entropy alloy die-casting in step 3) of Example 1.

[0039] Figure 2 This is the SEM image of the aluminum-based entropy alloy die-casting in step 3) of Example 1.

[0040] Figure 3 This is the stress-strain curve of the aluminum-based entropy alloy die casting in step 3) of Example 1. DETAILED DESCRIPTION

[0041] The present invention will be further explained and illustrated below in conjunction with specific embodiments.

[0042] All raw materials in the examples and comparative examples are conventional products purchased from the market.

[0043] The refining agent in the embodiments and comparative examples is the rare earth multifunctional aluminum alloy slag removal refining agent ZS-AJ01c produced by Foshan Nanhai Lvyuan Metal Supporting Materials Co., Ltd.

[0044] The vacuum die-casting equipment used in the embodiment is a TOYO BD-250V5 die-casting machine equipped with a Wanda vacuum system.

[0045] Embodiment 1:

[0046] Aluminum-based entropy alloy Al 80 Si8Mg4Cu4Zn4, its preparation raw materials are shown in the following table:

[0047] Table 1 Aluminum-based entropy alloy Al 80 Preparation raw materials table of Si8Mg4Cu4Zn4

[0048]

[0049]

[0050] The above aluminum-based entropy alloy Al 80 The preparation method of Si8Mg4Cu4Zn4 is as follows:

[0051] 1) Melting: Place the prepared raw materials at 100°C and dry for 6 hours, then add pure aluminum into the melting furnace, control the heating rate to be 150°C / h and heat from room temperature to 700°C±5°C, wait for the aluminum ingot to be completely melted, then add Al-Si20 master alloy and Al-Cu50 master alloy in sequence, wait for the alloy to be completely melted, stir for 20 minutes, cool down to 650°C±5°C, then add Al-Mg50 master alloy preheated to 180°C±10°C and pure zinc preheated to 180°C±10°C, wait for the alloy and pure zinc to be completely melted, keep warm at 650°C±5°C for 20 minutes to obtain a melt;

[0052] 2) Refining and degassing: add a refining agent to the melt, the amount of the refining agent is 0.4% of the melt mass, and after refining at 650℃±5℃ for 20min, skim off the scum, then introduce high-purity argon gas for degassing, let it stand for 15min, and then remove the slag on the surface of the melt to obtain refined aluminum liquid (sample the melt to test the chemical composition, and prepare for die casting after the composition is qualified);

[0053] 3) Die casting: Inject refined aluminum liquid into a mold coated with zinc oxide release agent and preheated to 180°C ± 10°C, evacuate the mold cavity to a vacuum degree of ≤ 100 mbar, control the injection speed at high speed to 2.5 m / s, the low speed to 0.3 m / s, and the boost pressure to 95 MPa for vacuum die casting to obtain aluminum-based entropy alloy die castings;

[0054] 4) Heat treatment: The aluminum-based entropy alloy die casting was placed in a resistance furnace and treated at 450°C for 0.5 h, 1 h, 2 h and 3 h respectively (to obtain samples with different solution treatment times), then immersed in room temperature water for quenching, and then left at room temperature for 12 h to obtain the aluminum-based entropy alloy Al 80 Si8Mg4Cu4Zn4.

[0055] Performance Test:

[0056] a) The X-ray diffraction (XRD) pattern of the aluminum-based entropy alloy die casting in step 3) of this embodiment is as follows: Figure 1 As shown in the scanning electron microscope (SEM) image Figure 2 shown.

[0057] Depend on Figure 1 It can be seen that the aluminum-based entropy alloy die-casting is composed of α-Al phase, eutectic Si phase, Al2Cu phase, Mg2Si phase, MgZn2 phase and Q phase.

[0058] Depend on Figure 2It can be seen that the bright white area is the MgZn2 phase, the Al2Cu phase is irregular and coarse, with a similar contrast to the MgZn2 phase, the Q phase is needle-shaped with a gray contrast, while the eutectic Si phase is light gray, the Mg2Si phase is dark, and the rest is the α-Al phase.

[0059] b) The stress-strain relationship curve of the aluminum-based entropy alloy die casting in step 3) of this embodiment is as follows Figure 3 shown.

[0060] Depend on Figure 3 It can be seen that the compressive strength of the aluminum-based entropy alloy die-casting reaches 816MPa, and the fracture plasticity reaches 19.3%, which has excellent plastic deformation ability; in addition, the yield strength of the aluminum-based entropy alloy die-casting reaches 538MPa.

[0061] c) The aluminum-based entropy alloy Al with different solution treatment times in this embodiment was tested using a universal material testing machine from Shimadzu, Japan. 80 The room temperature mechanical properties of Si8Mg4Cu4Zn4 were tested (aluminum-based entropy alloy die castings were used as reference), and the test results are shown in the following table:

[0062] Table 2 Aluminum-based entropy alloy Al 80 Room temperature mechanical properties test results of Si8Mg4Cu4Zn4

[0063]

[0064] It can be seen from Table 2 that after the aluminum-based entropy alloy die castings are heat treated, the yield strength, compressive strength and fracture plasticity of the alloy are increased. Among them, the yield strength, compressive strength and fracture plasticity of the alloy obtained by solution treatment at 450℃ for 1h are the largest.

[0065] d) The aluminum-based entropy alloy Al in this embodiment with a solution treatment time of 1 h was tested using an electronic mechanical universal testing machine CMT 5105. 80 Si8Mg4Cu4Zn4 was subjected to high temperature (200℃~400℃) mechanical property test, and the test results are shown in the following table:

[0066] Table 3 Aluminum-based entropy alloy Al 80 High temperature mechanical properties test results of Si8Mg4Cu4Zn4

[0067] Test temperature (℃) Yield strength (MPa) Compressive strength(MPa) Fracture plasticity (%) 200 529 702 >40 250 467 493 >40 300 332 352 >40 350 248 265 >40 400 178 198 >40

[0068] It can be seen from Table 3 that aluminum-based entropy alloy Al 80 The yield strength and compressive strength of Si8Mg4Cu4Zn4 at 200°C are 529MPa (close to the room temperature yield strength) and 702MPa respectively, and the fracture plasticity exceeds 40%; as the temperature gradually increases, the aluminum-based entropy alloy Al 80Si8Mg4Cu4Zn4 gradually softens. At 300°C, the alloy can still show an ultra-high yield strength of 332MPa, and the compressive strength still reaches 352MPa. When the temperature reaches 400°C, the yield strength and compressive strength are 178MPa and 198MPa respectively, followed by continuous strain softening.

[0069] Embodiment 2:

[0070] Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The raw materials for its preparation are shown in the following table:

[0071] Table 4 Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 Table of raw materials for preparation

[0072] raw material Mass percentage (%) Pure aluminum (same as Example 1) 24.10 Al-Si20 master alloy (same as Example 1) 40.85 Al-Mg50 master alloy (same as Example 1) 7.06 Al-Cu50 master alloy (same as Example 1) 18.48 Pure zinc (same as Example 1) 9.51

[0073] The above aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The preparation method is as follows:

[0074] 1) Melting: Place the prepared raw materials at 100°C and dry for 6 hours, then add pure aluminum into the melting furnace, control the heating rate to be 150°C / h and heat from room temperature to 700°C±5°C, wait for the aluminum ingot to be completely melted, then add Al-Si20 master alloy and Al-Cu50 master alloy in sequence, wait for the alloy to be completely melted, stir for 20 minutes, cool down to 650°C±5°C, then add Al-Mg50 master alloy preheated to 180°C±10°C and pure zinc preheated to 180°C±10°C, wait for the alloy and pure zinc to be completely melted, keep warm at 650°C±5°C for 20 minutes to obtain a melt;

[0075] 2) Refining and degassing: add a refining agent to the melt, the amount of the refining agent is 0.4% of the melt mass, and after refining at 650℃±5℃ for 20min, skim off the scum, then introduce high-purity argon gas for degassing, let it stand for 15min, and then remove the slag on the surface of the melt to obtain refined aluminum liquid (sample the melt to test the chemical composition, and prepare for die casting after the composition is qualified);

[0076] 3) Die casting: Inject refined aluminum liquid into a mold coated with zinc oxide release agent and preheated to 180°C ± 10°C, evacuate the mold cavity to a vacuum degree of ≤ 100 mbar, control the injection speed at high speed to 2.5 m / s, the low speed to 0.3 m / s, and the boost pressure to 95 MPa for vacuum die casting to obtain aluminum-based entropy alloy die castings;

[0077] 4) Heat treatment: The aluminum-based entropy alloy die casting was placed in a resistance furnace and treated at 450°C for 0.5 h, 1 h, 2 h and 3 h respectively (to obtain samples with different solution treatment times), then immersed in room temperature water for quenching, and then left at room temperature for 12 h to obtain the aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 .

[0078] Performance Test:

[0079] a) The aluminum-based entropy alloy Al with different solution treatment times in this embodiment 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The room temperature mechanical properties test (test method is the same as in Example 1) was carried out, and the test results are shown in the following table:

[0080] Table 5 Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 Room temperature mechanical properties test results

[0081]

[0082] It can be seen from Table 5 that after the aluminum-based entropy alloy die castings are heat treated, the yield strength, compressive strength and fracture plasticity of the alloy are increased. Among them, the yield strength, compressive strength and fracture plasticity of the alloy obtained by solution treatment at 450℃ for 1h are the largest.

[0083] b) The aluminum-based entropy alloy Al in this embodiment with a solution treatment time of 1 h 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The high temperature mechanical properties test was carried out (the test method is the same as in Example 1), and the test results are shown in the following table:

[0084] Table 6 Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu4.4 Zn 4.4 High temperature mechanical properties test results

[0085] Test temperature (℃) Yield strength(MPa) Compressive strength(MPa) Fracture plasticity (%) 200 538 726 >40 250 478 502 >40 300 344 371 >40 350 258 272 >40 400 187 206 >40

[0086] It can be seen from Table 6 that aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The yield strength and compressive strength at 200°C reach 538MPa (close to the room temperature yield strength) and 726MPa respectively, and the fracture plasticity exceeds 40%; as the temperature gradually increases, the aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 Gradually softening, at 300°C, the alloy can still show an ultra-high yield strength of 344MPa, and the compressive strength can still reach 371MPa. When the temperature reaches 400°C, the yield strength and compressive strength are 187MPa and 206MPa respectively, followed by continuous strain softening.

[0087] Embodiment 3:

[0088] Aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The raw materials for its preparation are shown in the following table:

[0089] Table 7 Aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 Table of raw materials for preparation

[0090] raw material Mass percentage (%) Pure aluminum (same as Example 1) 36.64 Al-Si20 master alloy (same as Example 1) 34.10 Al-Mg50 master alloy (same as Example 1) 5.90 Al-Cu50 master alloy (same as Example 1) 15.42 Pure zinc (same as Example 1) 7.94

[0091] The above aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The preparation method is as follows:

[0092] 1) Melting: Place the prepared raw materials at 100°C and dry for 6 hours, then add pure aluminum into the melting furnace, control the heating rate to be 150°C / h and heat from room temperature to 700°C±5°C, wait for the aluminum ingot to be completely melted, then add Al-Si20 master alloy and Al-Cu50 master alloy in sequence, wait for the alloy to be completely melted, stir for 20 minutes, cool down to 650°C±5°C, then add Al-Mg50 master alloy preheated to 180°C±10°C and pure zinc preheated to 180°C±10°C, wait for the alloy and pure zinc to be completely melted, keep warm at 650°C±5°C for 20 minutes to obtain a melt;

[0093] 2) Refining and degassing: add a refining agent to the melt, the amount of the refining agent is 0.4% of the melt mass, and after refining at 650℃±5℃ for 20min, skim off the scum, then introduce high-purity argon gas for degassing, let it stand for 15min, and then remove the slag on the surface of the melt to obtain refined aluminum liquid (sample the melt to test the chemical composition, and prepare for die casting after the composition is qualified);

[0094] 3) Die casting: Inject refined aluminum liquid into a mold coated with zinc oxide release agent and preheated to 180°C ± 10°C, evacuate the mold cavity to a vacuum degree of ≤ 100 mbar, control the injection speed at high speed to 2.5 m / s, the low speed to 0.3 m / s, and the boost pressure to 95 MPa for vacuum die casting to obtain aluminum-based entropy alloy die castings;

[0095] 4) Heat treatment: The aluminum-based entropy alloy die casting was placed in a resistance furnace and treated at 450°C for 0.5 h, 1 h, 2 h and 3 h respectively (to obtain samples with different solution treatment times), then immersed in room temperature water for quenching, and then left at room temperature for 12 h to obtain the aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 .

[0096] Performance Test:

[0097] a) The aluminum-based entropy alloy Al with different solution treatment times in this embodiment 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The room temperature mechanical properties test (test method is the same as in Example 1) was carried out, and the test results are shown in the following table:

[0098] Table 8 Aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 Room temperature mechanical properties test results

[0099]

[0100]

[0101] It can be seen from Table 8 that after the aluminum-based entropy alloy die castings are heat treated, the yield strength, compressive strength and fracture plasticity of the alloy are increased. Among them, the yield strength, compressive strength and fracture plasticity of the alloy obtained by solution treatment at 450℃ for 1h are the largest.

[0102] b) The aluminum-based entropy alloy Al in this embodiment with a solution treatment time of 1 h 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The high temperature mechanical properties test was carried out (the test method is the same as in Example 1), and the test results are shown in the following table:

[0103] Table 9 Aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 High temperature mechanical properties test results

[0104] Test temperature (℃) Yield strength (MPa) Compressive strength(MPa) Fracture plasticity (%) 200 515 688 >40 250 447 481 >40 300 316 339 >40 350 228 258 >40 400 167 183 >40

[0105] It can be seen from Table 9 that aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The yield strength and compressive strength at 200°C reach 515MPa (close to the room temperature yield strength) and 688MPa respectively, and the fracture plasticity exceeds 40%; as the temperature gradually increases, the aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 Gradually softening, at 300°C, the alloy can still show an ultra-high yield strength of 316MPa, and the compressive strength can still reach 339MPa. When the temperature reaches 400°C, the yield strength and compressive strength are 167MPa and 183MPa respectively, followed by continuous strain softening.

[0106] Comparative Example 1:

[0107] Aluminum-based entropy alloy Al 80 Si8Mg4Cu4Zn4, the raw materials for preparation are the same as those in Example 1, and the preparation method is as follows:

[0108] 1) Gravity casting: inject refined aluminum liquid (same as in Example 1) into a mold coated with a zinc oxide release agent, then place the mold in a box-type resistance furnace and heat it to 250° C., then take out the mold and assemble it, and start gravity pouring when the mold cavity temperature drops to 200° C. to obtain an aluminum-based entropy alloy die casting;

[0109] 2) Heat treatment: The aluminum-based entropy alloy die casting was placed in a resistance furnace and treated at 450°C for 0.5 h, 1 h, 2 h and 3 h respectively (to obtain samples with different solution treatment times), then immersed in room temperature water for quenching, and then left at room temperature for 12 h to obtain the aluminum-based entropy alloy Al 80 Si8Mg4Cu4Zn4.

[0110] Performance Test:

[0111] a) The aluminum-based entropy alloy Al with different solution treatment times in this comparative example 80 Si8Mg4Cu4Zn4 was subjected to room temperature mechanical property test (test method is the same as in Example 1), and the test results are shown in the following table:

[0112] Table 10 Aluminum-based entropy alloy Al 80 Room temperature mechanical properties test results of Si8Mg4Cu4Zn4

[0113]

[0114] b) For the aluminum-based entropy alloy Al in this comparative example, the solid solution treatment time is 1 h 80 Si8Mg4Cu4Zn4 was subjected to high temperature mechanical property test (test method is the same as in Example 1), and the test results are shown in the following table:

[0115] Table 11 Aluminum-based entropy alloy Al 80 High temperature mechanical properties test results of Si8Mg4Cu4Zn4

[0116] Test temperature (℃) Yield strength (MPa) Compressive strength(MPa) Fracture plasticity (%) 200 402 558 >40 250 323 378 >40 300 208 236 >40 350 126 149 >40 400 77 102 >40

[0117] It can be seen from Table 10 and Table 11 that the aluminum-based entropy alloy Al in this comparative example 80 Si8Mg4Cu4Zn4 and the aluminum-based entropy alloy Al in Example 1 80 Compared with Si8Mg4Cu4Zn4, the room temperature mechanical properties and high temperature mechanical properties are significantly worse, indicating that vacuum die-cast aluminum-based entropy alloys have better mechanical properties than gravity cast aluminum-based entropy alloys.

[0118] Comparative Example 2:

[0119] Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu4.4 Zn 4.4 The raw materials are prepared in the same manner as in Example 2, and the preparation method is as follows:

[0120] 1) Gravity casting: inject refined aluminum liquid (same as in Example 2) into a mold coated with a zinc oxide release agent, then place the mold in a box-type resistance furnace and heat it to 250° C., then take out the mold and assemble it, and start gravity casting when the mold cavity temperature drops to 200° C. to obtain an aluminum-based entropy alloy die casting;

[0121] 2) Heat treatment: The aluminum-based entropy alloy die casting was placed in a resistance furnace and treated at 450°C for 0.5 h, 1 h, 2 h and 3 h respectively (to obtain samples with different solution treatment times), then immersed in room temperature water for quenching, and then left at room temperature for 12 h to obtain the aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 .

[0122] Performance Test:

[0123] a) The aluminum-based entropy alloy Al with different solution treatment times in this comparative example 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The room temperature mechanical properties test (test method is the same as in Example 1) was carried out, and the test results are shown in the following table:

[0124] Table 12 Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 Room temperature mechanical properties test results

[0125]

[0126] b) For the aluminum-based entropy alloy Al in this comparative example, the solid solution treatment time is 1 h 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 The high temperature mechanical properties test was carried out (the test method is the same as in Example 1), and the test results are shown in the following table:

[0127] Table 13 Aluminum-based entropy alloy Al 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 High temperature mechanical properties test results

[0128] Test temperature (℃) Yield strength (MPa) Compressive strength(MPa) Fracture plasticity (%) 200 421 569 >40 250 341 393 >40 300 224 259 >40 350 147 168 >40 400 95 121 >40

[0129] It can be seen from Table 12 and Table 13 that the aluminum-based entropy alloy Al in this comparative example 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 Compared with the aluminum-based entropy alloy Al in Example 2 78 Si 8.8 Mg 4.4 Cu 4.4 Zn 4.4 In comparison, the room temperature mechanical properties and high temperature mechanical properties are significantly worse, indicating that the vacuum die-cast aluminum-based entropy alloy has better mechanical properties than the gravity cast aluminum-based entropy alloy.

[0130] Comparative Example 3:

[0131] Aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The raw materials are prepared in the same manner as in Example 3, and the preparation method is as follows:

[0132] 1) Gravity casting: inject refined aluminum liquid (same as in Example 3) into a mold coated with a zinc oxide release agent, then place the mold in a box-type resistance furnace and heat it to 250° C., then take out the mold and assemble it, and start gravity casting when the mold cavity temperature drops to 200° C. to obtain an aluminum-based entropy alloy die casting;

[0133] 2) Heat treatment: The aluminum-based entropy alloy die casting was placed in a resistance furnace and treated at 450°C for 0.5 h, 1 h, 2 h and 3 h respectively (to obtain samples with different solution treatment times), then immersed in room temperature water for quenching, and then left at room temperature for 12 h to obtain the aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 .

[0134] Performance Test:

[0135] a) The aluminum-based entropy alloy Al with different solution treatment times in this comparative example 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The room temperature mechanical properties test (test method is the same as in Example 1) was carried out, and the test results are shown in the following table:

[0136] Table 14 Aluminum-based entropy alloy Al 82Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 Room temperature mechanical properties test results

[0137]

[0138] b) For the aluminum-based entropy alloy Al in this comparative example, the solid solution treatment time is 1 h 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 The high temperature mechanical properties test was carried out (the test method is the same as in Example 1), and the test results are shown in the following table:

[0139] Table 15 Aluminum-based entropy alloy Al 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 High temperature mechanical properties test results

[0140]

[0141]

[0142] It can be seen from Table 14 and Table 15 that the aluminum-based entropy alloy Al in this comparative example 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 Compared with the aluminum-based entropy alloy Al in Example 3 82 Si 7.2 Mg 3.6 Cu 3.6 Zn 3.6 In comparison, the room temperature mechanical properties and high temperature mechanical properties are significantly worse, indicating that the vacuum die-cast aluminum-based entropy alloy has better mechanical properties than the gravity cast aluminum-based entropy alloy.

[0143] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An aluminum-based entropy alloy, characterized in that: The chemical formula is Al x Si y Mg z Cu u Zn v , where the subscripts correspond to the molar percentage of element atoms, x+y+z+u+v=100, x=78~82, y=7.2~8.8, z=3.6~4.4, u=3.6~4.4, v=3.6~4.

4.

2. The aluminum-based entropy alloy according to claim 1, characterized in that: The aluminum-based entropy alloy is made of the following raw materials in percentage by mass: Pure aluminum: 24.10% to 36.64%; Al-Si20 master alloy: 34.10%~40.85%; Al-Mg50 master alloy: 5.90%~7.06%; Al-Cu50 master alloy: 15.42%~18.48%; Pure zinc: 7.94%~9.51%.

3. The aluminum-based entropy alloy according to claim 2, characterized in that: The purity of the pure aluminum is ≥99.80%; the purity of the Al-Si20 master alloy, the Al-Mg50 master alloy and the Al-Cu50 master alloy are all ≥99.90%; the purity of the pure zinc is ≥99.00%.

4. A method for preparing an aluminum-based entropy alloy as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: 1) Melting: Dry the prepared raw materials, add them into a melting furnace for melting, and obtain a melt; 2) Refining and degassing: adding a refining agent to the melt for refining, and then degassing, standing and removing impurities to obtain refined aluminum liquid; 3) Die casting: inject refined aluminum liquid into the mold for vacuum die casting to obtain aluminum-based entropy alloy die castings; 4) Heat treatment: subjecting the aluminum-based entropy alloy die casting to solid solution treatment and aging treatment to obtain the aluminum-based entropy alloy.

5. The preparation method according to claim 4, characterized in that: Step 1) The smelting includes the following operations: adding pure aluminum into a smelting furnace, gradually heating up to 695°C to 705°C, and waiting for the aluminum ingot to be completely melted. Then, Al-Si20 master alloy and Al-Cu50 master alloy are added in sequence, and the alloy is completely melted, stirred for 15min to 25min, cooled to 645°C to 655°C, and then Al-Mg50 master alloy preheated to 170°C to 190°C and pure zinc preheated to 170°C to 190°C are added, and the alloy and pure zinc are completely melted, and kept warm for 15min to 25min.

6. The preparation method according to claim 4, characterized in that: The refining agent in step 2) is the rare earth multifunctional aluminum alloy slag removal refining agent ZS-AJ01c produced by Foshan Nanhai Lvyuan Metal Supporting Materials Co., Ltd.; the amount of the refining agent in step 2) is 0.3% to 0.5% of the mass of the melt.

7. The preparation method according to claim 4 or 6, characterized in that: Step 2) The refining is carried out at a temperature of 645°C to 655°C.

8. The preparation method according to claim 4, characterized in that: Step 3) The vacuum die-casting is carried out under the condition of vacuum degree ≤ 100 mbar.

9. The preparation method according to claim 4, characterized in that: The solution treatment in step 4) is carried out at a temperature of 445°C to 455°C for a treatment time of 0.5h to 3h; the aging treatment in step 4) is carried out at room temperature for a treatment time of 12h to 24h.

10. Use of the aluminum-based entropy alloy as claimed in any one of claims 1 to 3 in the aerospace field, the automotive industry field or the marine engineering field.

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