High-temperature-resistant high-strength plasticity nanoparticle modified magnesium alloy and preparation method thereof

Abstract

The application provides a high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy and a preparation method thereof. x The CoCrFeNi high-entropy alloy ingot is drawn to obtain a wire, the wire and a Ti wire are wound, and the Al x CoCrFeNiTi y high-entropy alloy powder is prepared by an electric explosion method. After the magnesium alloy is melted, the preheated Al x CoCrFeNiTi y high-entropy alloy powder is added into the magnesium alloy melt, is dispersed by ultrasonic after mechanical stirring, and is subjected to refining degassing, slag cleaning, casting, solid solution, water quenching and aging treatment to obtain the high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy. The high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy obtained by the application can realize high-temperature yield strength ≥188.2 MPa, tensile strength ≥277.4 MPa and elongation ≥14.2%, and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-toughness magnesium alloy, and particularly relates to a high-temperature-resistant high-strength-plasticity nano-particle modified magnesium alloy and a preparation method thereof. BACKGROUND

[0002] Magnesium alloy is the lightest metal structural material in industrial application, has the advantages of high specific strength, high specific stiffness, good electromagnetic shielding, easy recycling, rich resources, etc., and is an ideal structural material in the fields of automobiles and aerospace. However, the magnesium alloy prepared by a conventional method has problems such as significant decline in high-temperature mechanical properties, which limits the further application of the magnesium alloy. In the application field above 250 DEG C (such as the core components of power systems such as automobile engine pistons), the high-temperature resistance of the traditional magnesium alloy will decline. The existing technology mainly solves the above problems by using plastic deformation processes such as equal-channel angular extrusion and high-pressure torsion or adding a large amount of Dy and other noble metals. Although the above method can alleviate the performance decline of the alloy under high-temperature use, it will cause the following problems: first, the plastic deformation process is relatively complex, the process is long, the cost of added raw materials is increased, and the added elements need high-temperature heat treatment; second, it is difficult to realize the synchronous improvement of high-temperature strength and plasticity of the alloy and industrialized production. Therefore, how to reduce the raw material addition cost, simplify the production process, and simultaneously improve the strength and plasticity of the magnesium alloy under high-temperature use and realize industrialized production is a technical problem to be solved at present. SUMMARY

[0003] In order to solve the above technical problems, the application provides a high-temperature-resistant high-strength-plasticity nano-particle modified magnesium alloy, and a preparation method thereof.

[0004] (1) under the protection of argon, Al, Co, Cr, Fe and Ni are 2-6 times of cyclic arc smelting and cooling treatment according to the mass ratio of 3.1-8.6:23.5-25.5:20.8-22.5:21.3-24.3:23.5-25.6 to obtain Al x1 CoCrFeNi high-entropy alloy ingot; then the Al x1 CoCrFeNi high-entropy alloy ingot is drawn into a wire material at a speed of 3x10 -3 ~5x10 -2 mm / min at 700-900 DEG C, the wire material and Ti wire are wound according to the mass ratio of 94.6:5.4-98.7:1.3, and then Al x2 CoCrFeNiTi y high-entropy alloy powder composed of nano-particles with an average size of 100-300 nm is obtained after electric explosion initiation treatment.

[0005] Each arc melting treatment is that the alloying elements are melted by means of ignition arc at 1500-2200℃;

[0006] The electric explosion initiation treatment is that the voltage is 5-25kV and the current is 10-100A;

[0007] The Al x2 CoCrFeNiTi y The components of the high-entropy alloy powder mainly include: Al: 3.0-8.9%, Co: 20.4-25.6%, Cr: 20.0-23.5%, Fe: 20.3-24.5%, Ni: 21.5-24.9%, and Ti: 2.0-5.5%;

[0008] (2) After the pure magnesium is melted by heating to 650-680℃ under the protection of a mixed gas of CO2 and SF6 in a volume ratio of 9:1, the Mg-30Y, Mg-30Nd and Mg-30Gd intermediate alloys and pure Zr preheated to 250-350℃ are added, the molten magnesium alloy is obtained after complete melting, stirring for 2-9 minutes, and holding for 10-30 minutes;

[0009] The components of the magnesium alloy melt are: Y: 3.0-3.9 wt.%, Nd: 0.6-1.3 wt.%, Gd: 0.2-0.8 wt.%, Zr: 0.4-1.2 wt.%, unavoidable impurities ≤0.1 wt.%, and the balance of Mg;

[0010] (3) The magnesium alloy melt obtained in step (2) is heated to 750-770℃, and the Al x2 CoCrFeNiTi y The high-entropy alloy powder is subjected to mechanical stirring for 3-9 minutes and ultrasonic treatment at 20.34-20.38 kHz for 1-7 minutes, and then subjected to high-temperature refining, slag removal, casting, solid solution, water quenching and aging treatment at 720-750℃ to obtain a high-temperature-resistant high-strength-plasticity nano-particle-modified magnesium alloy;

[0011] The Al x2 CoCrFeNiTi y The mass ratio of the high-entropy alloy powder to the magnesium alloy is 0.025-0.425%:1;

[0012] The solid solution treatment is holding at 500-540℃ for 0.5-5 hours;

[0013] The aging treatment is holding at 200-250℃ for 6-16 hours;

[0014] The high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy has a yield strength of ≥188.2 MPa, a tensile strength of ≥277.4 MPa and an elongation of ≥14.2% at ≥300 ℃.

[0015] Further, the electric arc melting treatment in step (1) is performed at 1600-1900 ℃ by igniting an electric arc; the electric explosion initiation treatment has a voltage of 10-20 kV and a current of 15-35 A; the Al x2 CoCrFeNiTi y The high-entropy alloy powder mainly comprises Al: 3.2-8.8%, Co: 22.8-24.5%, Cr: 20.1-22.6%, Fe: 21.5-23.9%, Ni: 22.0-24.3% and Ti: 2.1-5.4%.

[0016] Further, the magnesium alloy melt component in step (2) comprises Y: 3.2-3.8 wt.%, Nd: 0.8-1.2 wt.%, Gd: 0.4-0.7 wt.%, Zr: 0.5-1.1 wt.% and unavoidable impurities ≤0.1 wt.%, with the balance being Mg.

[0017] Further, the Al x2 CoCrFeNiTi y The mass ratio of the high-entropy alloy powder to the magnesium alloy is 0.04-0.25%:1; the solid solution treatment is performed at 510-530 ℃ for 1-5 hours; and the aging treatment is performed at 220-240 ℃ for 7-12 hours. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A scanning electron microscope microstructure diagram of the magnesium alloy 4 obtained in Comparative Example 1;

[0019] Figure 2 A high-temperature tensile curve of the magnesium alloy 4 obtained in Comparative Example 1 at 300 ℃;

[0020] Figure 3 A scanning electron microscope microstructure diagram of the high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy 1 obtained in Example 1;

[0021] Figure 4 A high-temperature tensile curve of the high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy 1 obtained in Example 1 at 300 ℃;

[0022] Figure 5 A scanning electron microscope microstructure diagram of the high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy 2 obtained in Example 2;

[0023] Figure 6 High temperature tensile curve of high temperature resistant high strength plasticity nano-particle modified magnesium alloy 2 obtained in Example 2 at 310℃;

[0024] Figure 7 Scanning electron microscope structure diagram of high temperature resistant high strength plasticity nano-particle modified magnesium alloy 3 obtained in Example 3;

[0025] Figure 8 High temperature tensile curve of high temperature resistant high strength plasticity nano-particle modified magnesium alloy 3 obtained in Example 3 at 330℃. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0027] Example 1

[0028] High temperature resistant high strength plasticity nano-particle modified magnesium alloy 1, a preparation method thereof comprises the following steps:

[0029] (1) under the protection of argon, Al, Co, Cr, Fe and Ni are 5 times of cyclic arc smelting and cooling treatment according to the mass ratio of 5.6:24.6:21.7:23.4:24.6 to obtain Al 0.5 CoCrFeNi high-entropy alloy ingot; then the Al 0.5 CoCrFeNi high-entropy alloy ingot is drawn into a wire material at 750℃ with a speed of 5×10 -3 mm / min, the wire material and Ti wire are wound according to the mass ratio of 97.6:2.4, and Al 0.478 CoCrFeNiTi 0.121 high-entropy alloy powder composed of nano-particles with an average size of 220nm;

[0030] Each arc smelting treatment is: the alloy elements are smelted at 1800℃ by means of ignition arc;

[0031] The electric explosion initiation treatment is: voltage: 15 kV, current 20A;

[0032] According to the mass percentage, the Al 0.478 CoCrFeNiTi 0.121The main components of high-entropy alloy powder include: Al: 5.6%, Co: 23.1%, Cr: 21.6%, Fe: 23.1%, Ni: 24.0%, Ti: 2.6%;

[0033] (2) Under the protection of a CO2 and SF6 mixed gas with a volume ratio of 9:1, pure magnesium is heated to 660°C to melt, and then Mg-30Y, Mg-30Nd, Mg-30Gd master alloys preheated to 340°C and pure Zr are added. After complete melting, the mixture is stirred for 3 minutes and then kept at the temperature for 12 minutes to obtain a magnesium alloy melt. The composition of the magnesium alloy melt by mass percentage is: Y: 3.6 wt.%, Nd: 0.9 wt.%, Gd: 0.7 wt.%, Zr: 0.6 wt.%, unavoidable impurities ≤ 0.1 wt.%, and the balance is Mg.

[0034] (3) Heat the magnesium alloy melt obtained in step (2) to 765 °C, and then add the Al from step (1) after preheating treatment. 0.478 CoCrFeNiTi 0.121 High-entropy alloy powder was mechanically stirred for 4 minutes and ultrasonically treated at 20.34 kHz for 3 minutes, and then refined, degassed, cleaned, cast, dissolved, water-quenched and aged at 735℃ to obtain high-temperature resistant, high-strength and ductile nanoparticle modified magnesium alloy 1.

[0035] The Al 0.478 CoCrFeNiTi 0.121 The mass ratio of high-entropy alloy powder to magnesium alloy melt is 0.05%:1;

[0036] The solution treatment is performed by holding the solution at 515 °C for 4 hours.

[0037] The aging treatment is as follows: heat treatment at 235 ℃ for 8 hours;

[0038] Scanning electron microscopy microstructure of high-temperature resistant, high-strength, and ductile nanoparticle-modified magnesium alloy 1 is shown below. Figure 3 As shown, its average grain size is ~48.9 μm, and alloy 1 contains uniformly distributed nanoparticles. Figure 4 The results show that the high-temperature resistant, high-strength, and ductile nanoparticle-modified magnesium alloy 1 has a high-temperature yield strength of 195.5 MPa, a tensile strength of 279.9 MPa, and an elongation of 15.4% at 300℃; compared with step (3) without the addition of Al 0.478 CoCrFeNiTi 0.121 Compared with magnesium alloys made from high-entropy alloy powder, the high-temperature yield strength, tensile strength, and plasticity of the high-temperature resistant, high-strength, and high-plasticity nanoparticle-modified magnesium alloy 1 obtained in the example were increased by 14.7%, 14.9%, and 11.6%, respectively.

[0039] Example 2

[0040] The preparation method of the high-temperature resistant, high-strength, and ductile nanoparticle-modified magnesium alloy 2 includes the following steps:

[0041] (1) Under argon protection, Al, Co, Cr, Fe, and Ni were subjected to three cycles of electric arc melting and cooling treatment in a mass ratio of 3.4:25.4:22.1:23.8:25.3 to finally obtain Al. 0.3 CoCrFeNi high-entropy alloy ingot; then Al 0.3 CoCrFeNi high-entropy alloy ingots were fired at 820℃ at a rate of 8×10 -3 The wire is drawn into a filament at a speed of mm / min, and then wound with a Ti wire at a mass ratio of 95.2:4.8. After undergoing an electro-explosion initiation treatment, Al is obtained. 0.290 CoCrFeNiTi 0.243 High-entropy alloy powder, which is composed of nanoparticles with an average size of 150 nm;

[0042] Each arc melting process is described as follows: the alloying elements are melted at 1700℃ by igniting an electric arc;

[0043] The aforementioned electrical explosion initiation process is as follows: voltage: 18kV, current: 25A;

[0044] The Al, by weight percentage 0.290 CoCrFeNiTi 0.243 The main components of high-entropy alloy powder include: Al: 3.8%, Co: 24.2%, Cr: 21.7%, Fe: 22.1%, Ni: 23.3%, Ti: 4.9%;

[0045] (2) Under the protection of a CO2 and SF6 mixed gas with a volume ratio of 9:1, pure magnesium is heated to 675 °C to melt, and then Mg-30Y, Mg-30Nd, Mg-30Gd master alloys preheated to 300 °C and pure Zr are added. After complete melting, the mixture is stirred for 4 minutes and then kept at the temperature for 15 minutes to obtain a magnesium alloy melt. The composition of the magnesium alloy melt by mass percentage is: Y: 3.2 wt.%, Nd: 1.1 wt.%, Gd: 0.5 wt.%, Zr: 1.0 wt.%, unavoidable impurities ≤ 0.1 wt.%, and the balance is Mg.

[0046] (3) Heat the magnesium alloy melt obtained in step (2) to 760 °C, and then add the Al from step (1) after preheating treatment. 0.290 CoCrFeNiTi 0.243High-entropy alloy powder was mechanically stirred for 5 minutes and ultrasonically treated at 20.36 kHz for 5 minutes, and then refined, degassed, cleaned, cast, dissolved, water-quenched and aged at 730 ℃ to obtain high-temperature resistant, high-strength and ductile nanoparticle modified magnesium alloy 2.

[0047] The Al 0.290 CoCrFeNiTi 0.243 The mass ratio of high-entropy alloy powder to magnesium alloy melt is 0.125%:1;

[0048] The solution treatment is performed by holding the solution at 525 °C for 2 hours.

[0049] The aging treatment is as follows: heat preservation at 225 ℃ for 11 hours;

[0050] Scanning electron microscopy microstructure of high-temperature resistant, high-strength, and ductile nanoparticle-modified magnesium alloy 2 is shown below. Figure 5 As shown, its average grain size is ~40.3 μm, and alloy 2 contains uniformly distributed nanoparticles. Figure 6 The results show that alloy 2 has a high-temperature yield strength of 202.7 MPa, a tensile strength of 284.0 MPa, and an elongation of 17.3% at 310℃. This is different from step (3) without the addition of Al. 0.290 CoCrFeNiTi 0.243 Compared with magnesium alloys made of high-entropy alloy powder, the high-temperature yield strength, tensile strength and plasticity of the high-temperature resistant, high-strength and high-plasticity nanoparticle modified magnesium alloy 2 obtained in the example were increased by 18.9%, 16.6% and 25.4%, respectively.

[0051] Example 3

[0052] The preparation method of the high-temperature resistant, high-strength, and ductile nanoparticle-modified magnesium alloy 3 includes the following steps:

[0053] (1) Under argon protection, Al, Co, Cr, Fe, and Ni were subjected to four cycles of electric arc melting and cooling treatment in a mass ratio of 7.7:24.1:21.2:22.6:24.4 to obtain Al. 0.7 CoCrFeNi high-entropy alloy ingot; then Al 0.7 CoCrFeNi high-entropy alloy ingots were fired at 880℃ at a rate of 1×10 -2 The wire is drawn into a filament at a speed of mm / min, and then wound with a Ti filament at a mass ratio of 96.5:3.5. After undergoing an electro-explosion initiation treatment, Al is obtained. 0.686 CoCrFeNiTi 0.255 High-entropy alloy powder, which is composed of nanoparticles with an average size of 280 nm;

[0054] Each arc melting treatment is that: the alloying elements are treated by arc ignition at 1850 ℃;

[0055] The electric explosion initiation treatment is: voltage: 14 kV, current 30 A;

[0056] The Al 0.686 CoCrFeNiTi 0.255 The composition of the high-entropy alloy powder mainly includes: Al: 7.4%, Co: 23.2%, Cr: 20.5%, Fe: 22.0%, Ni: 23.2%, and Ti: 3.5%;

[0057] (2) Under the protection of a mixed gas of CO2 and SF6 in a volume ratio of 9:1, pure magnesium is heated to 670 ℃ for melting, and then Mg-30Y, Mg-30Nd, and Mg-30Gd intermediate alloys and pure Zr preheated at 275 ℃ are added. After complete melting, stirring is performed for 8 minutes, and then the temperature is maintained for 22 minutes to obtain a magnesium alloy melt. The magnesium alloy melt contains Y: 3.8 wt.%, Nd: 1.2 wt.%, Gd: 0.6 wt.%, Zr: 0.9 wt.%, unavoidable impurities ≤0.1 wt.%, and the balance of Mg;

[0058] (3) The magnesium alloy melt obtained in step (2) is heated to 760 ℃, and then Al 0.686 CoCrFeNiTi 0.255 The high-entropy alloy powder is subjected to mechanical stirring for 7 minutes and ultrasonic treatment at 20.38 kHz for 4 minutes, and then subjected to high-temperature refining, degassing, slag removal, casting, solid solution, water quenching, and aging treatment to obtain a high-temperature-resistant high-strength plastic nanometer particle modified magnesium alloy 3.

[0059] The Al 0.686 CoCrFeNiTi 0.255 The mass ratio of the high-entropy alloy powder to the magnesium alloy melt is 0.185%:1.

[0060] The solid solution treatment is performed at 520 ℃ for 3 hours.

[0061] The aging treatment is performed at 235 ℃ for 9 hours.

[0062] The scanning electron microscope microstructure of the high-temperature-resistant high-strength plastic nanometer particle modified magnesium alloy 3 is shown in Figure 7 The average grain size is ~52.1 μm, and the alloy 3 contains uniformly distributed nanometer particles. Figure 8The alloy 3 has high temperature yield strength of 188.2 MPa, tensile strength of 277.4 MPa and elongation of 14.2% at 330 ℃. Compared with the alloy without adding Al 0.686 CoCrFeNiTi 0.255 Compared with the magnesium alloy powder, the high temperature yield strength, tensile strength and plasticity of the high temperature high-strength and plasticity nano-particle modified magnesium alloy 3 obtained in the embodiment are increased by 7.6%, 13.0% and 2.9% respectively.

[0063] Comparative example 1

[0064] A magnesium alloy 4 is prepared by the following method:

[0065] (1) Under the protection of a mixed gas of CO2 and SF6 in a volume ratio of 9:1, pure magnesium is heated to 675 ℃ for melting, and then Mg-30Y, Mg-30Nd and Mg-30Gd intermediate alloys and pure Zr preheated at 300 ℃ are added. After complete melting, the mixture is stirred for 4 minutes and then kept for 15 minutes to obtain a magnesium alloy melt. The components of the magnesium alloy melt are as follows in terms of mass percentage: Y: 3.2 wt.%, Nd: 1.1 wt.%, Gd: 0.5 wt.%, Zr: 1.0 wt.%, unavoidable impurities ≤0.1 wt.%, and the balance being Mg;

[0066] (2) After refining, degassing, casting, solid solution, water quenching and aging treatment at 730 ℃, the magnesium alloy 4 is obtained;

[0067] The solid solution treatment is keeping at 525 ℃ for 2 hours;

[0068] The aging treatment is keeping at 225 ℃ for 11 hours;

[0069] The scanning electron microscope microstructure of the magnesium alloy 4 is shown in Figure 1 The microstructure of the alloy is coarse, the second phase is unevenly distributed, and the average grain size is about 85.4 μm. Figure 2 The alloy 4 has high temperature yield strength of 170.4 MPa, ultimate tensile strength of 243.5 MPa and elongation of 13.8% at 300 ℃.

[0070] The embodiment 1-3 of the present application differs from the comparative example 1 in that:

[0071] Compared with Comparative Example 1, the average grain size of the magnesium alloy 1 obtained in Example 1 of the present application is 40.3 μm, which is refined by 42.7% compared with the magnesium alloy prepared in Comparative Example 1. The high-temperature yield strength, tensile strength and elongation of the magnesium alloy 1 at 300℃ are 195.5 MPa, 279.9 MPa and 15.4%, which are increased by 14.7%, 14.9% and 11.6% compared with the magnesium alloy 4 prepared in Comparative Example 1.

[0072] Compared with Comparative Example 1, the average grain size of the magnesium alloy 2 obtained in Example 2 of the present application is 48.9 μm, which is refined by 52.8% compared with the magnesium alloy prepared in Comparative Example 1. The high-temperature yield strength, tensile strength and elongation of the magnesium alloy 2 at 320℃ are 202.7 MPa, 284.0 MPa and 17.3%, which are increased by 18.9%, 16.6% and 25.4% compared with the magnesium alloy 4 prepared in Comparative Example 1.

[0073] Compared with Comparative Example 1, the average grain size of the magnesium alloy 3 obtained in Example 3 of the present application is 52.1 μm, which is refined by 38.9% compared with the magnesium alloy prepared in Comparative Example 1. The high-temperature yield strength, tensile strength and elongation of the magnesium alloy 3 at 330℃ are 188.2 MPa, 277.4 MPa and 14.2%, which are increased by 7.6%, 13.0% and 2.9% compared with the magnesium alloy 4 prepared in Comparative Example 1.

[0074] Comparative Example 2

[0075] The highest performance of the WE43 alloy prepared in the article “Effect of Dy addition on microstructure and mechanical properties of Mg−4Y−3Nd−0.4Zr alloy” by Liu et al. in Trans. Nonferrous Met. Soc. China 27 (2017) 797−803 is Mg−4Y−3Nd−0.4Zr−0.3Dy, i.e. more Dy is added compared with the alloy in the examples, and the mass ratio is 0.3 wt.%, and the yield strength of the alloy at 300℃ is 185 MPa, the tensile strength is 252 MPa, and the elongation is 10.8%.

[0076] The application and Comparative Example 2 belong to the same series of alloys, and the application can still obtain strength and plasticity significantly superior to Comparative Example 2 at a temperature greater than that of Comparative Example 2, and thus has more excellent high-temperature resistance, and simultaneously improves the strength and plasticity of the alloy compared with Comparative Example 2, when Dy and the content of the additive elements are omitted and the content of the alloy elements of the application is less than 6.5 wt.%, which is less than 7.7 wt.% of the content of the elements of Comparative Example 2.

[0077] Table 1 Comparison of grain size, high-temperature yield strength, tensile strength and elongation in Comparative Example and each embodiment

[0078] Sample Grain size Yield strength Tensile strength Elongation Comparative Example 1 85.4 μm 170.4 MPa 243.5 MPa 13.8% Example 1 48.9 μm 195.5 MPa 279.9 MPa 15.4% Example 2 40.3 μm 202.7 MPa 284.0 MPa 17.3% Example 3 52.1 μm 188.2 MPa 277.4 MPa 14.2% Comparative Example 2 - 185 MPa 252 MPa 10.8%

[0079] In summary: compared with the prior art, the application adds nanoparticles with a size of ≤300 nm and a content of ≤0.185 wt.%, and the grains obtained by the application are uniformly distributed and significantly refined (grain size controlled to ≤52.1 μm), which reduces the amount of raw materials and the amount of Dy and other rare and precious earth elements added, that is, the alloy obtained by the application still has higher strength and plasticity than the alloy obtained by the prior art at a temperature equal to or higher than that of the prior art, and industrial production is realized, which breaks the technical bottleneck that the strength or plasticity of the prior art is reduced at high temperature, it is difficult to industrialize production, and the strength and plasticity of the prior art are difficult to be simultaneously improved. In addition, the components, proportions and process parameters of all embodiments of the application are different, and the strength and plasticity of the alloy obtained by each embodiment are different, which shows that the excellent effect obtained by the application is not determined by a certain component, proportion, process or process parameter, but is determined by the synergistic regulation of the interaction between the components, the proportion, the process and the process parameters, and only within the scope of the claims of the application, can the advantages obtained by the application be realized.

Claims

1. A high temperature resistant, high strength plasticity, nano-particle modified magnesium alloy, characterized in that, The preparation method comprises the following steps: (1) under the protection of argon, Al, Co, Cr, Fe and Ni are subjected to 2-6 times of cycle arc melting and cooling treatment according to the mass ratio of 3.1-8.6:23.5-25.5:20.8-22.5:21.3-24.3:23.5-25.6 to obtain Al x1 CoCrFeNi high-entropy alloy ingot; Al x1 CoCrFeNi high-entropy alloy ingot is drawn into a wire at a speed of 3x10 -3 ~5x10 -2 mm / min at 700-900℃, the wire and Ti wire are wound according to the mass ratio of 94.6:5.4-98.7:1.3, and Al x2 CoCrFeNiTi y high-entropy alloy powder composed of nanoparticles with an average size of 100-300nm; The each arc melting treatment is: at 1500-2200 ℃, the alloy element is treated by igniting arc; The electric explosion initiation treatment is: voltage: 5-25 kV, current 10-100 A; The Al is 3.0-8.9% by mass x2 CoCrFeNiTi y The high-entropy alloy powder mainly comprises: Al: 3.0-8.9%, Co: 20.4-25.6%, Cr: 20.0-23.5%, Fe: 20.3-24.5%, Ni: 21.5-24.9%, and Ti: 2.0-5.5%. (2) under the protection of CO2 and SF6 mixed gas with a volume ratio of 9:1, pure magnesium is heated to 650-680 ℃ for melting, then 250-350 ℃ preheated Mg-30Y, Mg-30Nd, Mg-30Gd intermediate alloy and pure Zr are added, after complete melting, stirring for 2-9 minutes, and then holding for 10-30 minutes to obtain a magnesium alloy melt; According to mass percentage, the magnesium alloy melt component is: Y: 3.0-3.9 wt.%, Nd: 0.6-1.3 wt.%, Gd: 0.2-0.8 wt.%, Zr: 0.4-1.2 wt.%, unavoidable impurities ≤0.1 wt.%, and the balance is Mg; (3) the magnesium alloy melt obtained in step (2) is heated to 750-770℃, and the preheated Al in step (1) is added again x2 CoCrFeNiTi y The high-entropy alloy powder is subjected to mechanical stirring for 3-9 minutes and ultrasonic treatment at 20.34-20.38 kHz for 1-7 minutes, and then subjected to high-temperature refining degassing, slag removal, casting, solid solution, water quenching and aging treatment at 720-750℃ to obtain a high-temperature-resistant high-strength-plasticity nano-particle-modified magnesium alloy. The Al x2 CoCrFeNiTi y The mass ratio of the high-entropy alloy powder to the magnesium alloy is 0.025-0.425:

1. The solid solution treatment is: holding at 500-540 ℃ for 0.5-6 hours; The aging treatment is: holding at 200-250 ℃ for 6-16 hours; The high-temperature-resistant high-strength plasticity nano-particle modified magnesium alloy has a yield strength ≥188.2 MPa, a tensile strength ≥277.4 MPa, and an elongation ≥14.2% at ≥300 ℃.

2. The high temperature resistant, high strength plasticity, nano particle modified magnesium alloy according to claim 1, characterized in that, The electric arc melting treatment in step (1) is that the alloying elements are melted by igniting arc at 1600-1900 DEG C; the electric explosion initiation treatment is that the voltage is 10-20 kV and the current is 15-35 A; the Al x2 CoCrFeNiTi y The components of the high-entropy alloy powder mainly include: Al: 3.2-8.8%, Co: 22.8-24.5%, Cr: 20.1-22.6%, Fe: 21.5-23.9%, Ni: 22.0-24.3%, and Ti: 2.1-5.4%.

3. The high temperature resistant, high strength plasticity, nano particle modified magnesium alloy of claim 1, wherein, According to mass percentage, the magnesium alloy melt component in step (2) is: Y: 3.2-3.8 wt.%, Nd: 0.8-1.2 wt.%, Gd: 0.4-0.7 wt.%, Zr: 0.5-1.1 wt.%, unavoidable impurities ≤0.1 wt.%, and the balance is Mg.

4. The high temperature resistant, high strength plasticity, nano particle modified magnesium alloy of claim 1, wherein, Al in step (3) x2 CoCrFeNiTi y The mass ratio of the high-entropy alloy powder to the magnesium alloy is 0.04-0.25:1; the solid solution treatment is: heat preservation at 510-530 DEG C for 1-5 hours; and the aging treatment is: heat preservation at 220-240 DEG C for 7-12 hours.

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