Magnesium-lithium alloy material and preparation method thereof

Abstract

The invention belongs to the technical field of magnesium-lithium alloys, and particularly relates to a magnesium-lithium alloy material and a preparation method thereof. The magnesium-lithium alloy material comprises the following components in percentage by mass: Li, Al, Zn and the balance of Mg, the composite material is prepared at room temperature by adopting a multidirectional compression plastic deformation process. Under the condition that rare metals are not added, aluminum and zinc elements have a synergistic effect with magnesium and lithium, and through subsequent room-temperature multidirectional compression plastic deformation process treatment, the strength of the alloy is improved, and meanwhile, the toughness is well maintained. The improvement of the mechanical property of the magnesium-lithium alloy is based on dislocation movement blocking, and dislocation blocking in multi-directional compression mainly comes from a sliding band formed in a grain boundary and a compression process. The larger the accumulative strain is, the more the dislocations needing to be started for deformation are, and the larger the blocking force is; the staggered moving directions of the multi-direction loading positions are more than those of single-direction loading starting, and the staggered moving directions are more easily hindered by the formed sliding belt. The larger the hindering force is, the more obvious the resistance to the external load is, namely the more obvious the increase of the strength and the hardness is.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnesium-lithium alloys, and particularly relates to a magnesium-lithium alloy material and a preparation method thereof. Background Art

[0002] Magnesium-lithium alloy (also known as ultra-light alloy) is the lightest metal structural material in engineering applications so far, with a density of only 1.35 - 1.65 g / cm 3 , which is 1 / 3 - 1 / 2 lighter than aluminum alloy. It has high specific strength, high specific stiffness and excellent formability, and can replace aluminum alloy and magnesium alloy to manufacture aileron skins, instrument panels, electrical housings, pod brackets, loaders, and spacecraft frames, spherical gyroscopes, accelerometer housings, gyroscope mounting plate and other components on aircraft. It has great economic benefits and strategic significance in the weight reduction requirements of aerospace components.

[0003] The addition of lithium element can effectively reduce the c / a ratio of the hcp lattice parameter of α-Mg, activate more non-basal slip between lattice planes. For example, prismatic {101 _ 0} and pyramidal {101 _ 2} planes will be successfully activated, significantly improving the plasticity of magnesium alloy. The formability of magnesium-lithium alloy is much better than that of traditional magnesium alloy. However, as a metal structural material, the absolute strength of commercial magnesium-lithium alloy is currently low. The as-cast magnesium-lithium alloy is generally about 100 MPa, and the wrought magnesium-lithium alloy is about 200 MPa. Therefore, the weight reduction effect is weakened, hindering its wide application.

[0004] Therefore, in order to increase the strength of magnesium-lithium alloy, researchers have tried to achieve solid solution strengthening or form intermetallic compounds to play a dispersion strengthening role by adding alloying elements such as Al, Zn, Ca, Cu, Ag, Sr and rare earth elements Y, Ce, Nd, La, etc. Although the performance has been improved to a certain extent, there has been no fundamental change. The main reasons are that there are segregation and uneven distribution of alloying elements in the matrix, and some alloying elements exist in the form of large compounds, unable to form an effective second-phase particle strengthening mechanism; in addition, magnesium-lithium alloy is prone to over-aging during the aging process, and the precipitated metastable hardening phase is prone to transform into a stable softening phase.

[0005] In recent years, composite strengthening has been adopted, such as using electrophoretic deposition technology, friction stir, cold rolling and multi-walled carbon nanotubes to jointly strengthen Mg-14Li-1Al alloy. Although this method can effectively improve the mechanical properties, the process is too long and the cost is too high.

[0006] Therefore, it is very necessary to develop a high-strength and low-cost magnesium-lithium alloy preparation technology that does not add rare metals and heavy metals and has a short preparation process. Summary of the Invention

[0007] The purpose of the present invention is to provide a magnesium-lithium alloy material and a preparation method thereof, which solve the problems of segregation and uneven distribution of alloying elements in the matrix and high cost of composite strengthening existing in the existing preparation process of adding alloying elements.

[0008] The present invention is realized through the following technical solutions:

[0009] The present invention discloses a magnesium-lithium alloy material, which includes the following components in mass percentage: Li 2%-5%, Al 2%-4%, Zn 2%-4%, and the balance is Mg;

[0010] It is prepared by a multi-directional compression plastic deformation process at room temperature.

[0011] Furthermore, the yield strength of the magnesium-lithium alloy material is 161-258 MPa, the compressive strength is 334-408 MPa, and the hardness is 87.2-117.4 HV.

[0012] The present invention also discloses a preparation method of the above-mentioned magnesium-lithium alloy material, which includes the following steps:

[0013] S1. Solution treatment

[0014] At 300-350 °C, the magnesium-lithium alloy is heated under a protective atmosphere and then quenched in water to room temperature to obtain a solution-state alloy;

[0015] S2. Machining

[0016] The solution-state alloy is processed into a cuboid to obtain a specimen;

[0017] S3. Room-temperature multi-directional compression plastic deformation

[0018] At room temperature, loads are applied sequentially from three directions of the specimen. According to the principle of constant volume, the side lengths of the compressed cuboid maintain the ratio before plastic deformation, and so on, cycling multiple compressions, and the true strain accumulated by multiple compressions is obtained by accumulating the true strain.

[0019] Furthermore, in S3, the process of the room-temperature multi-directional compression plastic deformation is specifically as follows:

[0020] Assume that the ratio of the side lengths of the cuboid is a:b:c, a>b>c. Loads are applied sequentially from three directions of the specimen. First, load in the direction of side length a. According to the principle of constant volume, side length a is compressed to c, and the other two sides will increase from b and c to a and b. The side lengths of the compressed cuboid still maintain the ratio of a:b:c; then, compress the newly generated side length a to c, and so on, cycling multiple compressions. The true strain Δε = ln(a / c) for each compression.

[0021] Furthermore, a = b + Δ, c = b - Δ, and Δ = 0.2-0.8.

[0022] Further, in S3, the loading device used for multi-directional compressive plastic deformation is a press or a testing machine with a programmable control function, and the speed is controlled at 200 - 300 mm / min.

[0023] Further, in S1, the magnesium-lithium alloy is heated in a protective atmosphere for 1 - 2 hours.

[0024] Further, in S2, S2 specifically is: processing the solution-treated alloy into a cuboid, deburring, and polishing to obtain a specimen.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The present invention discloses a magnesium-lithium alloy material, which, in terms of mass percentage, comprises the following components: Li 2% - 5%, Al 2% - 4%, Zn 2% - 4%, and the balance is Mg. The present invention does not add rare metals, has few element components, and has a low cost. The purpose of adding Al and Zn elements is to strengthen by forming solid solutions or forming second phases. In the case of not adding rare metals, the Al and Zn elements cooperate with Mg and Li, and through subsequent room-temperature multi-directional compressive plastic deformation process treatment, the strength of the alloy increases, and at the same time, the toughness is well maintained. The improvement of the mechanical properties of the magnesium-lithium alloy is based on the hindrance of dislocation movement. In multi-directional compression, the dislocation hindrance mainly comes from grain boundaries and slip bands formed during the compression process. The larger the ∑Δε strain, the more dislocations need to be activated for deformation, and the greater the resistance. The directions of dislocation activation in multi-directional loading are more than those in single-directional loading and are more easily hindered by the formed slip bands. The greater the resistance, the more obvious the resistance to the externally applied load, that is, the more significant the increase in strength and hardness. Therefore, this strengthening technology can more easily strengthen the material than traditional plastic deformation.

[0027] The present invention also discloses a preparation method of the magnesium-lithium alloy material. First, a single-phase alloy is obtained through solution treatment to improve the plasticity and toughness of the material, providing better conditions for subsequent compression. Second, a supersaturated solid solution is obtained, and alloying elements are precipitated as dispersed phases through subsequent aging to further improve the mechanical properties of the alloy. Then, it is machined into a cuboid specimen, and finally, a multi-directional compression plastic deformation process is adopted at room temperature. After applying a compression load, obvious slip bands are generated inside the alloy. As the loading direction continuously changes, slip bands in different directions are formed inside the grains, and the slip bands in different directions intersect with each other. The slip bands are hindered by the original grain boundaries and usually do not cross the grain boundaries within a certain deformation degree, so the intersection mainly occurs inside the grains. Different from other plastic deformations, in this method, the loading direction continuously cycles, the grain shape basically does not change significantly, no obvious texture is formed, and there is no anisotropy phenomenon. The core technical point of the present invention lies in achieving a significant improvement in the mechanical properties of the magnesium-lithium alloy through the processing technology of multi-directional compression plastic deformation at room temperature, solving the problem of insufficient strength of the magnesium-lithium alloy in the prior art.

[0028] The present invention adopts a multi-directional compression plastic deformation process at room temperature, enabling simultaneous strengthening and forming, preparing high-precision products, eliminating blank cleaning and some machining processes, and having a low total cost. Usually, strengthening only refers to the strengthening of materials. However, in the present invention, through multi-directional compression plastic deformation, while strengthening, the forming of parts can also be completed. And when performing the multi-directional compression plastic deformation process at room temperature, there are no problems such as oxidation and cooling shrinkage, and the precision is easy to control. Ordinary material forming is carried out at high temperature and it is difficult to achieve high precision. Since this method directly reaches a very high precision, subsequent machining processes for parts can be omitted.

[0029] Furthermore, a press or testing machine with a programmable control function is used for multi-directional compression plastic deformation at room temperature, which can be completed through existing equipment, with mature and reliable technology and relatively low investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a microstructural diagram after solution treatment at 350°C for 1 h;

[0031] Figure 2 It is a schematic diagram of the process of multi-directional compression plastic deformation at room temperature;

[0032] Figure 3is the microstructure of a magnesium-lithium alloy after different numbers of multi-directional compressions; among them, (a) is the microstructure of the magnesium-lithium alloy after 48 compressions, with a cumulative strain ∑Δε of 1.9; (b) is the microstructure of the magnesium-lithium alloy after 100 compressions, with a cumulative strain ∑Δε of 4.0; (c) is the microstructure of the magnesium-lithium alloy after 142 compressions, with a cumulative strain ∑Δε of 5.7; (d) is the microstructure of the magnesium-lithium alloy after 190 compressions, with a cumulative strain ∑Δε of 7.6;

[0033] Figure 4 are the mechanical properties under different cumulative strains. Specific Embodiments

[0034] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments.

[0035] The detailed description of the embodiments of the present invention provided in the following drawings is not intended to limit the scope of the claimed invention, but merely represents a selected embodiment of the present invention. Based on the drawings and embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0036] The features and properties of the present invention are further described in detail below in conjunction with the embodiments.

[0037] The magnesium-lithium alloy material to be prepared in the present invention, in terms of mass percentage, its chemical composition and element content are: Li 2%-5%, Al 2%-4%, Zn 2%-4%, and the rest is Mg.

[0038] The specific preparation process includes the following steps:

[0039] S1. Solution treatment

[0040] At 300-350 °C, heat the magnesium-lithium alloy in a protective atmosphere for 1-2 hours, and then rapidly quench it in water to room temperature to obtain a solutionized alloy.

[0041] S2. Machining

[0042] Machine the solutionized alloy into a cuboid, remove burrs, and perform polishing treatment to obtain a specimen.

[0043] S3. Room-temperature multi-directional compressive plastic deformation

[0044] Load the specimen sequentially from three directions. According to the principle of constant volume, the side lengths of the compressed cuboid remain in the same ratio as before plastic deformation. Repeat the compression process multiple times in this way, and accumulate the true strain of each compression to obtain the cumulative strain ∑Δε.

[0045] Example 1

[0046] The present invention discloses a magnesium-lithium alloy material, which includes the following components by mass percentage: Li 3%, Al 3%, Zn 3%, and the balance is Mg.

[0047] The preparation method of the magnesium-lithium alloy material specifically includes the following steps:

[0048] S1. Solution treatment:

[0049] Place the magnesium-lithium alloy in an atmosphere protection furnace and heat it at 350 °C for 1 hour, then quench it in water to room temperature to obtain a solution-treated alloy. Figure 1 It is the microstructure after solution treatment at 350 °C × 1 h.

[0050] S2. Machining

[0051] Use wire cutting to machine the solution-treated alloy into a cuboid, and control the side lengths of the three sides of the cuboid in the ratio of 25:24.5:24. Polish the six surfaces of the cuboid specimen with sandpapers of multiple specifications in sequence to remove burrs and ensure that the two opposite ends of the specimen are parallel.

[0052] S3. Room-temperature multi-directional compressive plastic deformation

[0053] The loading device is a press with a programmable control function, and the speed is controlled at 250 mm / min.

[0054] As Figure 2 shown, load the specimen sequentially from three directions. First, load in the direction of the 25 side length. According to the principle of constant volume, when the 25 side length is compressed to 24, the other two sides will increase from 24.5 and 24 to 25 and 24.5, and the side lengths of the compressed cuboid still remain in the ratio of 25:24.5:24. Then, compress the newly generated 25 side length to 24, and repeat the compression process multiple times in this way. The true strain of each compression Δε = ln(25 / 24) ≈ 0.04. Accumulate the true strain of each compression to obtain the cumulative strain ∑Δε.

[0055] Figure 3is the microstructure of a magnesium-lithium alloy subjected to different multi-directional compressions. Figure (a) shows the microstructure of the magnesium-lithium alloy after 48 passes of compression, with the cumulative strain ∑Δε being 1.9; Figure (b) shows the microstructure of the magnesium-lithium alloy after 100 passes of compression, with the cumulative strain ∑Δε being 4.0; Figure (c) shows the microstructure of the magnesium-lithium alloy after 142 passes of compression, with the cumulative strain ∑Δε being 5.7; Figure (d) shows the microstructure of the magnesium-lithium alloy after 190 passes of compression, with the cumulative strain ∑Δε being 7.6.

[0056] It can be observed that after applying the compressive load, obvious slip bands are generated inside the alloy. As the loading direction continuously changes, slip bands in different directions are formed inside the grains, and the slip bands in different directions intersect with each other. As ∑Δε increases, the number and density of slip bands in different directions continuously increase, and the intersections become denser, and the grains are continuously refined. The slip bands are hindered by the original grain boundaries and usually do not cross the grain boundaries within a certain degree of deformation, so the intersections are mainly formed inside the grains. Different from other plastic deformations, the loading direction of this method continuously cycles, the grain shape basically does not change significantly, no obvious texture is formed, and there is no anisotropy phenomenon. Figure 3 As shown, the mechanical properties under different cumulative strains are also different. As the cumulative strain increases, the yield strength, compressive strength, and hardness gradually increase, indicating that the mechanical properties have been improved.

[0057] As Figure 4 shown, the mechanical properties under different cumulative strains are also different. As the cumulative strain increases, the yield strength, compressive strength, and hardness gradually increase, indicating that the mechanical properties have been improved.

[0058] The improvement of the mechanical properties of the magnesium-lithium alloy is based on the hindrance of dislocation movement. In multi-directional compression, the dislocation hindrance mainly comes from the grain boundaries and the slip bands formed during the compression process. The larger the ∑Δε strain, the more dislocations need to be activated for deformation, and the greater the hindrance force; the dislocation activation directions in multi-directional loading are more than those in single-directional loading and are more easily hindered by the formed slip bands. The greater the hindrance force, the more obvious the resistance to the externally applied load, that is, the more significant the increase in strength and hardness. Therefore, this strengthening technology can strengthen the material more easily than traditional plastic deformation.

[0059] Example 2

[0060] The present invention discloses a magnesium-lithium alloy material, which includes the following components in mass percentage: Li 2%, Al 2%, Zn 2%, and the rest is Mg.

[0061] The preparation method of this magnesium-lithium alloy material specifically includes the following steps:

[0062] S1. Solution treatment:

[0063] At 300 °C, place the magnesium-lithium alloy in an atmosphere protection furnace and heat it for 2 hours, and then quench it in water to room temperature to obtain a solution-treated alloy.

[0064] S2. Machining

[0065] The solid solution alloy was processed into a cuboid using a milling machine, and the lengths of the three sides of the cuboid were controlled at a ratio of 25:24.5:24. The six faces of the cuboid specimen were deburred and polished in sequence using sandpaper of multiple specifications to ensure that the two opposite ends of the specimen were parallel.

[0066] S3, Multi-directional compression plastic deformation at room temperature

[0067] The loading device adopts a press with program-controlled function, and the speed is controlled at 250mm / min.

[0068] like Figure 2 As shown, the sample is loaded from three directions in sequence, first loading the 25.2 side length direction. According to the principle of volume invariance, the 25.2 side length is compressed to 24.8, and the other two sides will increase from 25, 24.8 to 25.2, 25. The length of the compressed cuboid side still maintains the ratio of 25.2:25:24.8. Then, the newly generated 25.2 side length is compressed to 24.8, and so on for multiple compression cycles. Each compression true strain Δε=ln(25.2 / 24.8)≈0.016. The cumulative strain ∑Δε is obtained by accumulating the true strains of multiple compressions.

[0069] Figure 3 Figure 2 is the microstructure of magnesium-lithium alloy after different multi-directional compression. (a) is the microstructure of magnesium-lithium alloy after 48 compressions, and the cumulative strain ∑Δε is 1.997; (b) is the microstructure of magnesium-lithium alloy after 100 compressions, and the cumulative strain ∑Δε is 4.16; (c) is the microstructure of magnesium-lithium alloy after 142 compressions, and the cumulative strain ∑Δε is 5.907; (d) is the microstructure of magnesium-lithium alloy after 190 compressions, and the cumulative strain ∑Δε is 7.904.

[0070] After applying the compressive load, obvious slip bands are generated inside the alloy. As the loading direction changes continuously, slip bands in different directions are formed inside the grains, and the slip bands in different directions intersect with each other. As ∑Δε increases, the number and density of slip bands in different directions continue to increase, the denser the intersection, the more refined the grains. The slip bands are hindered by the original grain boundaries and usually do not cross the grain boundaries within a certain degree of deformation. Therefore, the intersection is mainly formed inside the grains. Unlike other plastic deformations, this method continuously cycles the loading direction, the grain shape basically does not change significantly, no obvious texture is formed, and there is no anisotropy.

[0071] As shown in Table 1, the mechanical properties under different cumulative strains are also different. With the increase of cumulative strain, the yield strength, compressive strength and hardness gradually increase, indicating that the mechanical properties have been improved.

[0072] Table 1

[0073] Cumulative strain Yield strength / MPa Compressive strength / MPa Hardness / HV 0 139 272 72.3 1.997 155 328 84.8 4.16 189 343 97.5 5.907 228 373 107.8 7.904 247 395 112.9

[0074] Example 3

[0075] The present invention discloses a magnesium-lithium alloy material, which, in terms of mass percentage, comprises the following components: 5% of Li, 4% of Al, 4% of Zn, and the balance is Mg.

[0076] The preparation method of the magnesium-lithium alloy material specifically comprises the following steps:

[0077] S1. Solution treatment:

[0078] At 320 °C, the magnesium-lithium alloy is placed in an atmosphere protection furnace and heated for 2 hours, and then quenched in water to room temperature to obtain a solution-state alloy.

[0079] S2. Machining

[0080] The solution-state alloy is machined into a cuboid by a milling machine, and the side lengths of three sides of the cuboid are controlled according to the ratio of 23.8:23:22.6. The six surfaces of the cuboid specimen are polished successively with sandpapers of multiple specifications to remove burrs and polished to ensure that the opposite ends of the specimen are parallel.

[0081] S3. Room-temperature multi-directional compressive plastic deformation

[0082] The loading device is a press with a programmed control function, and the speed is controlled at 250 mm / min.

[0083] As Figure 2 shown, loading is carried out successively from three directions of the specimen, and first load the 23-side length direction. According to the principle of volume invariance, the 23.8-side length is compressed to 22.6, and the other two sides will increase from 23 and 22.6 to 23.8 and 23, and the side lengths of the compressed cuboid still maintain the ratio of 23.8:23:22.6. Then, compress the newly generated 23.8-side length to 22.6, and so on for multiple cycles of compression. The true strain Δε for each compression = ln(23.8 / 22.6) ≈ 0.0348. The cumulative strain ∑Δε is obtained by accumulating the true strains of multiple compressions.

[0084] Figure 3 are the microstructures of the magnesium-lithium alloy after different multi-directional compressions. Figure (a) is the microstructure of the magnesium-lithium alloy after 48 compressions, and the cumulative strain ∑Δε is 1.669; Figure (b) is the microstructure of the magnesium-lithium alloy after 100 compressions, and the cumulative strain ∑Δε is 3.478; Figure (c) is the microstructure of the magnesium-lithium alloy after 142 compressions, and the cumulative strain ∑Δε is 4.939; Figure (d) is the microstructure of the magnesium-lithium alloy after 190 compressions, and the cumulative strain ∑Δε is 6.609.

[0085] After applying a compressive load, obvious slip bands are generated inside the alloy. As the loading direction continuously changes, slip bands in different directions are formed inside the grains, and the slip bands in different directions intersect with each other. With the increase of ∑Δε, the number and density of slip bands in different directions continuously increase, and the intersections become denser, and the grains are continuously refined. The slip bands are hindered by the original grain boundaries and usually do not cross the grain boundaries within a certain degree of deformation, so the intersections are mainly formed inside the grains. Different from other plastic deformations, the loading direction of this method continuously cycles, the grain shape basically does not change significantly, no obvious texture is formed, and there is no anisotropy phenomenon.

[0086] As shown in Table 2, the mechanical properties under different cumulative strains are also different. With the increase of the cumulative strain, the yield strength, compressive strength and hardness gradually increase, indicating that the mechanical properties have been improved.

[0087] Table 2

[0088]

[0089]

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope of the claims of the present invention.

Claims

1. A magnesium-lithium alloy material, characterized in that: In terms of mass percentage, it includes the following components: Li 2%-5%, Al 2%-4%, Zn 2%-4%, and the rest is Mg; It was prepared by multi-directional compression plastic deformation process at room temperature.

2. A magnesium-lithium alloy material according to claim 1, characterized in that: The magnesium-lithium alloy material has a yield strength of 161-258 MPa, a compression strength of 334-408 MPa, and a hardness of 87.2-117.4 HV.

3. The method for preparing a magnesium-lithium alloy material according to claim 1 or 2, characterized in that: The following steps are involved: S1. Solution treatment The magnesium-lithium alloy is heated at 300-350°C in a protective atmosphere, and then quenched in water to room temperature to obtain a solid solution alloy; S2. Machining The solid solution alloy is processed into a cuboid to obtain a sample; S3, Multi-directional compression plastic deformation at room temperature At room temperature, the sample is loaded in three directions in turn. According to the principle of volume invariance, the side length of the compressed cuboid maintains the ratio before plastic deformation. The compression is repeated multiple times in a cycle and the cumulative strain is obtained by adding up the true strains of multiple compressions.

4. The method for preparing a magnesium-lithium alloy material according to claim 3, characterized in that: In S3, the process of multi-directional compression plastic deformation at room temperature is specifically as follows: Assume that the ratio of the side length of the rectangular parallelepiped is a:b:c, a>b>c, and load the specimen from three directions in sequence. First load the side length direction of a. According to the principle of volume invariance, the side length of a is compressed to c, and the other two sides will increase from b and c to a and b. The side length of the compressed rectangular parallelepiped still maintains the ratio of a:b:c; then, compress the newly generated side length of a to c, and repeat the compression cycle for multiple times. The true strain Δε=ln(a / c) each time.

5. The method for preparing a magnesium-lithium alloy material according to claim 4, characterized in that: a=b+Δ, c=b-Δ, Δ=0.2-0.

8.

6. The method for preparing a magnesium-lithium alloy material according to claim 3, characterized in that: In S3, the loading device used for multi-directional compression plastic deformation is a press or testing machine with a programmable control function, and the speed is controlled at 200-300 mm / min.

7. The method for preparing a magnesium-lithium alloy material according to claim 3, characterized in that: In S1, the magnesium-lithium alloy is heated under a protective atmosphere for 1-2 hours.

8. The method for preparing a magnesium-lithium alloy material according to claim 3, characterized in that: In S2, S2 specifically includes: processing the solid solution alloy into a cuboid, removing burrs, and polishing to obtain a sample.

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