A high-plasticity and high-corrosion-resistant magnesium alloy and its preparation method and application

Abstract

The present invention discloses a high-plasticity, high-corrosion-resistant magnesium alloy comprising the following components by weight: Sn 1-6%, Al 0.1-1%, Zr 0.1-1%, and Mn 0.01-3%, with the balance being Mg and unavoidable impurities. By regulating the elemental composition of the magnesium alloy and combining it with a suitable extrusion process, the present invention achieves a magnesium alloy that combines high plasticity with high corrosion resistance, effectively resolving the difficulty in achieving a balance between high plasticity and high corrosion resistance in existing magnesium alloys.

Description

Technical Field

[0001] The present invention relates to a magnesium alloy, in particular to a magnesium alloy having both high plasticity and high corrosion resistance and a preparation method thereof. Background Art

[0002] Magnesium alloys have high specific strength and specific stiffness, but their widespread application is limited by their poor corrosion resistance and plasticity. Nowadays, the service environment of magnesium alloys is becoming increasingly harsh, especially for magnesium alloy profiles, which require both processability and corrosion resistance.

[0003] Magnesium alloys have an HCP structure and poor intrinsic plasticity. Conventional methods for improving the plasticity of magnesium alloys primarily rely on enhancing their non-basal slip ability. While this can improve the plasticity of magnesium alloys, the high chemical reactivity of non-basal crystal planes can also increase the corrosion tendency of magnesium alloys.

[0004] On the other hand, magnesium alloys have a high intrinsic chemical activity, making them extremely susceptible to corrosion. Improving the corrosion resistance of magnesium alloys is mainly achieved by reducing galvanic corrosion, controlling the amount of secondary phases, or reducing the number of crystal planes with high chemical reaction activity.

[0005] In the actual development of magnesium alloys, the plasticity-corrosion properties of magnesium alloys are a difficult issue to reconcile. Among the existing magnesium alloys, due to a certain conflict in the design concepts of high plasticity and high corrosion resistance, traditional magnesium alloys find it difficult to simultaneously meet these two requirements. Currently, there are a few research results on magnesium alloys that simultaneously improve plasticity and corrosion resistance. For example, Chinese patent application number CN113981286A discloses "A Corrosion-Resistant High-Strength Plastic Magnesium Alloy and Its Preparation Method." By adding trace amounts of rare earth elements cerium and samarium, the stability and density of the corrosion product film are improved, the corrosion of the alloy surface by chloride ions is hindered, localized corrosion is suppressed, and the corrosion resistance of the alloy is improved. At the same time, the preparation method of this patent can effectively control the size and distribution of the second phase in the magnesium alloy and refine the grain size, thereby successfully preparing a corrosion-resistant, high-strength plastic magnesium alloy. However, its preparation process is relatively complex, and the plasticity and corrosion resistance of the resulting magnesium alloy are not very good. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the aforementioned prior art by providing a magnesium alloy that, by regulating alloy composition, effectively reduces non-basal surface activity and simultaneously improves both plasticity and corrosion resistance. The present invention also provides a method for preparing the magnesium alloy and its application.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a high-plasticity and high-corrosion-resistant magnesium alloy, wherein the magnesium alloy contains the following components in weight percentage: Sn 1-6%, Al 0.1-1%, Zr 0.1-1%, Mn 0.01-3%, and the balance is Mg and unavoidable impurities.

[0008] The high-plasticity, high-corrosion-resistant magnesium alloy described herein accelerates the deposition of corrosion product films on the magnesium alloy by adding Sn, while Sn also significantly restricts the diffusion of Cl ions. Al and Zr are added to improve the plasticity of the magnesium alloy, while the addition of Mn effectively reduces the content of Fe, the main impurity in the magnesium alloy. If the Sn content is too low, the acceleration effect on the deposition of corrosion product films on the magnesium alloy is insignificant, and the technical effects of the present application cannot be achieved. If the Sn content is too high, precipitation phases may form, increasing galvanic corrosion. If the Al and Zr content is too low, the improvement in the plasticity of the magnesium alloy is insignificant. If the Al and Zr content is too high, precipitation phases may form. If the Mn content is too low, the reduction in the Fe content of the magnesium alloy is insignificant, while an increase in the Fe content significantly reduces the corrosion resistance of the magnesium alloy. Similarly, if the Mn content is too high, precipitation phases may form, adversely affecting the performance of the magnesium alloy. After repeated experiments and studies, the inventors of the present application found that by controlling the component content of the magnesium alloy within the specific range, the non-basal activity of the magnesium alloy can be effectively reduced, thereby overcoming the conflict between the high plasticity and corrosion resistance of magnesium alloys in the prior art that is difficult to match. The resulting magnesium alloy successfully combines the advantages of high plasticity and high corrosion resistance.

[0009] As a preferred embodiment of the high-plasticity, high-corrosion-resistant magnesium alloy of the present invention, the weight percentage of Sn in the magnesium alloy is 1-2%. When the weight percentage of Sn in the magnesium alloy is controlled at 1-2%, the combination of this amount of Sn and other elements can more appropriately deposit a corrosion product film on the magnesium alloy and better restrict Cl ion diffusion.

[0010] As a preferred embodiment of the high-plasticity, high-corrosion-resistant magnesium alloy of the present invention, the weight percentages of Al and Zr in the magnesium alloy are both 0.1-0.5%. When the weight percentages of Al and Zr in the magnesium alloy are 0.1-0.5% and 0.1-0.5%, respectively, they are combined with other elements to achieve a better effect on improving the plasticity of the magnesium alloy.

[0011] As a preferred embodiment of the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the mass ratio of Al to Zr is 1:1. The inventors of the present application have found that when the addition amounts of Al and Zr are the same, a mass ratio of Al to Zr of 1:1 significantly improves the plasticity of the magnesium alloy compared to other ratios.

[0012] As a preferred embodiment of the high-plasticity, high-corrosion-resistant magnesium alloy of the present invention, the weight percentage of Mn in the magnesium alloy is 1-2%. When the weight percentage of Mn in the magnesium alloy is 1-2%, the content of Fe among the inevitable impurities in the magnesium alloy can be effectively reduced, and the weight percentage of Fe in the magnesium alloy can be effectively controlled to be no more than 0.05%.

[0013] As a preferred embodiment of the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the unavoidable impurities include Fe, and the weight percentage of the Fe in the magnesium alloy is not higher than 0.05%. As an impurity inevitably introduced during the casting process, the presence of Fe will greatly reduce the corrosion resistance of the magnesium alloy. The inventors of the present application have found through experimental research that by adding Mn elements in a specific content range, AlFeMn compounds can be formed to reduce the impurity content in the magnesium alloy, thereby effectively avoiding the adverse effects of Fe in the impurities on the corrosion resistance of the magnesium alloy. When the weight percentage of Fe in the magnesium alloy is not higher than 0.05%, the adverse effects of Fe on the corrosion resistance of the magnesium alloy can be effectively reduced, so that the corrosion resistance of the resulting magnesium alloy is significantly improved.

[0014] As a preferred embodiment of the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the elongation of the magnesium alloy is greater than 15%, and the corrosion rate of the magnesium alloy in a 3.5% by mass NaCl solution is less than 0.3 mm / year.

[0015] In the present application, the inventors have effectively reduced the non-basal activity of the magnesium alloy by regulating the elemental composition in the magnesium alloy and combining it with a suitable extrusion process. The elongation of the prepared magnesium alloy can reach more than 15%, and the corrosion rate of the alloy in a 3.5% by mass NaCl solution is less than 0.3 mm / year. It has the advantages of both high plasticity and high corrosion resistance, effectively solving the problem that the high plasticity and high corrosion resistance of existing magnesium alloys are difficult to match.

[0016] In addition, another object of the present invention is to provide a method for preparing the high-plasticity and high-corrosion-resistant magnesium alloy with simple process steps and easy industrial promotion. To achieve this object, the technical solution adopted by the present invention is: a method for preparing a high-plasticity and high-corrosion-resistant magnesium alloy, the method comprising the following steps:

[0017] (1) Homogenization treatment: weigh the raw materials of each component according to the composition ratio of the magnesium alloy to prepare a magnesium ingot, and perform homogenization treatment on the prepared magnesium ingot at a treatment temperature of 500-550°C for 4-10 hours;

[0018] (2) Extrusion treatment: extruding the raw material after homogenization treatment in step (1) at an extrusion temperature of 300-340° C. and an extrusion ratio of (3-18):1;

[0019] (3) Heat treatment: The alloy extruded in step (2) is subjected to heat treatment at a temperature of 150 to 200° C. for 10 to 40 minutes to obtain a high-plasticity and high-corrosion-resistant magnesium alloy.

[0020] In the preparation method of the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the temperature and time of the homogenization treatment in step (1) have been repeatedly tested and explored. During the test and exploration process, the inventors of the present application found that if the homogenization temperature in step (1) is too high or the homogenization treatment time is too long, it will cause the grains to grow, affecting the mechanical properties of the prepared magnesium alloy. At the same time, if the homogenization temperature is too low or the homogenization treatment time is too short, the solid solution reaction will not be fully carried out, and the purpose of uniform distribution of the elements as a whole cannot be achieved. During the extrusion treatment process in step (2), the inventors of the present application found that the extrusion ratio also has an important influence on the performance of the magnesium alloy. If the extrusion ratio is too large, it will lead to difficulty in forming, and if the extrusion ratio is too small, the grain refinement effect obtained will not be strong enough, affecting the performance of the magnesium alloy finally obtained.

[0021] The method for preparing the high-plasticity and high-corrosion-resistant magnesium alloy described in the present invention has simple process steps. A homogenization treatment is first performed before extrusion. After the homogenization treatment, an extrusion treatment is performed at a specific extrusion temperature and extrusion ratio, and then a heat treatment is performed. By following specific steps and controlling process parameters such as the homogenization treatment temperature, treatment time, and extrusion ratio, the high-plasticity and high-corrosion-resistant magnesium alloy described in the present invention can be prepared.

[0022] As a preferred embodiment of the method for preparing the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the homogenization treatment temperature in step (1) is 530° C. and the treatment time is 8 hours.

[0023] As a preferred embodiment of the method for preparing the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the extrusion temperature in step (2) is 320° C. and the extrusion ratio is 6:1.

[0024] As a preferred embodiment of the method for preparing the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, the heat treatment temperature in step (3) is 180° C. and the treatment time is 30 minutes.

[0025] Finally, the present invention also provides applications of the aforementioned high-plasticity, high-corrosion-resistant magnesium alloy in consumer electronics (3C) products, automobiles, and ships. The high-plasticity, high-corrosion-resistant magnesium alloy described in the present invention can achieve an elongation exceeding 15%, and its corrosion rate in a 3.5% by mass NaCl solution is less than 0.3 mm / year. Combining high plasticity with high corrosion resistance, it can effectively meet the material performance requirements for the outer shells of consumer electronics, automobiles, and ships.

[0026] The magnesium alloy described in the present invention, through the addition of Sn element, which is an element with a strong deposition tendency, has a standard reaction Gibbs free energy of precipitation of -77Kcal / mol, which means that Sn is very easy to deposit during the corrosion process. The pre-deposited Sn plays a role similar to a modifier, greatly improving the density of crystal nuclei, so that the formation rate of corrosion products is accelerated. At the same time, considering that Sn is a cathode poisoning element, it can effectively block the cathode hydrogen evolution reaction process, reduce the surface self-corrosion current, and improve the corrosion resistance of the magnesium alloy. Al and Zr elements, as elements that optimize plasticity and improve the precipitation efficiency of the corrosion film, can effectively accelerate the deposition of the corrosion product film and improve plasticity. The Mn element reduces the impurity content in the alloy by combining with impurities such as Fe, and improves the mechanical and corrosion properties of the alloy. By regulating the elemental composition of the magnesium alloy and combining it with a suitable extrusion process, the magnesium alloy obtained can effectively reduce the non-basal activity of the magnesium alloy. The elongation of the prepared magnesium alloy can reach more than 15%. The corrosion rate of the alloy in a 3.5% by mass NaCl solution is less than 0.3 mm / year. Even if exposed to the electrolyte solution for a long time, it still exhibits excellent corrosion resistance. It has the advantages of high plasticity and high corrosion resistance, effectively solving the problem of the difficulty in matching the high plasticity and high corrosion resistance of existing magnesium alloys.

[0027] The magnesium alloy preparation method of the present invention is low-cost and simple to operate, facilitating its industrialization and widespread use. The magnesium alloy of the present invention is suitable for use in consumer electronics, automobiles, and ships. Due to its dual advantages of elongation exceeding 15% and corrosion rate less than 0.3 mm / year, it can meet the processing requirements of most magnesium alloys and far outperforms existing magnesium alloys, providing a higher-performance magnesium alloy option for applications in consumer electronics, automobiles, and ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is an electron microscope photograph of the magnesium alloy described in Example 1;

[0029] Figure 2 This is the electron backscatter diffraction result diagram of the magnesium alloy described in Example 1;

[0030] Figure 3This is a fracture photo of the magnesium alloy described in Example 1;

[0031] Figure 4 1 is the tensile curve of the magnesium alloy of Example 1 and Example 2;

[0032] Figure 5 This is a photo of the surface morphology of the magnesium alloy after the corrosion resistance test of Example 1, after the corrosion products are removed;

[0033] Figure 6 This is a photograph of the surface morphology of the magnesium alloy of Comparative Example 1 after the corrosion products were removed after the corrosion resistance test. DETAILED DESCRIPTION

[0034] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] Examples 1 to 12

[0036] The 12 embodiments of the high-plasticity and high-corrosion-resistant magnesium alloy of the present invention, wherein the magnesium alloys of embodiments 1 to 12 contain the components shown in Table 1:

[0037] Table 1 Composition of the magnesium alloys described in Examples 1 to 12

[0038]

[0039] The preparation methods of the magnesium alloys described in Examples 1 to 12 all include the following steps:

[0040] (1) Homogenization treatment: weighing the raw materials of each component according to the composition ratio of the magnesium alloy to prepare a magnesium ingot, and homogenizing the prepared magnesium ingot;

[0041] (2) Extrusion treatment: extruding the raw material after homogenization treatment in step (1);

[0042] (3) Heat treatment: The alloy obtained by extrusion in step (2) is subjected to heat treatment to obtain a high-plasticity and high-corrosion-resistant magnesium alloy.

[0043] In the preparation methods of the magnesium alloys described in Examples 1 to 12, the process parameters for each step are selected as shown in Table 2:

[0044] Table 2 Process parameters of the preparation method of the magnesium alloy described in Examples 1 to 12

[0045]

[0046] Example 13

[0047] Electron microscope photos, electron backscatter diffraction results, tensile curves, and fracture photo test experiments of the magnesium alloy of the present invention

[0048] 1. Electron microscope photos, electron backscatter diffraction results and fracture photos

[0049] The magnesium alloy obtained in Example 1 was used as an experimental object, and its electron microscope photos, electron backscatter diffraction results, and fracture photos were tested. The testing method was as follows:

[0050] Electron microscopy: A Nova Nano SEM 430 scanning electron microscope was used to observe the microstructure of the treated samples. Electron gun type: Schottky; field emission accelerating voltage: 0.2-30kV; electron imaging resolution: 1.1nm-1.5kV; backscattered electron imaging resolution: 1.5nm-15kV;

[0051] Electron backscatter diffraction test: MIRA3 scanning electron microscope was used, the average angle deviation of the pattern was MAD≤0.5, and the EBSD online calibration analysis speed was 640 points / second (8×8 binning).

[0052] Fracture test: Nova Nano SEM 430 scanning electron microscope was used to observe the microstructure of the stretched sample.

[0053] The test results are as follows Figures 1 to 3 shown.

[0054] Attachment Figure 1 In the figure, the black phase is the magnesium alloy matrix phase, and the white phase is the precipitation phase. Figure 1 It can be seen that the precipitated phase is dispersed, and the dispersed precipitated phase is conducive to the occurrence of uniform corrosion, making the film deposition more uniform, and improving the corrosion resistance of the magnesium alloy.

[0055] By the attached Figure 2 It can be seen that the grain size of the magnesium alloy of the present invention is relatively small.

[0056] By the attached Figure 3 It can be seen that the magnesium alloy of the present invention has obvious ductile fracture characteristics.

[0057] 2. Stretch curve

[0058] The magnesium alloys described in Example 1 and Example 2 were respectively used as experimental objects, and tensile test tests were performed on the magnesium alloys described in Example 1 and Example 2, respectively. The test method is as follows: the elongation of the magnesium alloy is tested in accordance with GB / T 228.1-2010 "Tensile tests on metallic materials - Part 1: Room temperature test methods".

[0059] The test results are as attached Figure 4 As shown. Figure 4 It can be seen that the magnesium alloys described in Examples 1 and 2 of the present invention both have an elongation greater than 15%.

[0060] The electron microscope photos, electron backscatter diffraction results, tensile curves, and fracture photos of the other embodiments described above all have similar results and are not described in detail here.

[0061] Example 14

[0062] Comparative test of elongation and corrosion resistance of the magnesium alloy of the present invention

[0063] This embodiment provides comparative examples 1 to 13. The components of the magnesium alloys in comparative examples 1 to 13 are shown in Table 3:

[0064] Table 3 Composition of the magnesium alloys described in Comparative Examples 1 to 13

[0065]

[0066]

[0067] In Table 3, Comparative Example 12 uses an equal amount of Gd to replace Sn; Comparative Example 13 uses an equal amount of Ca to replace Mn.

[0068] The preparation methods of the magnesium alloys described in Comparative Examples 1 to 13 are the same as those in Example 1 above.

[0069] The magnesium alloys of Examples 1 to 12 and Comparative Examples 1 to 13 were sampled respectively, and the mechanical properties and corrosion rate of each group of samples were tested. The test method is as follows:

[0070] The elongation of magnesium alloy is tested in accordance with GB / T 228.1-2010 “Tension tests on metallic materials - Part 1: Room temperature test methods”.

[0071] The simulated seawater corrosion rate is based on ASTM-G31-72 "Laboratory Immersion Corrosion Test of Metals".

[0072] The surface morphology photos of the magnesium alloys of Example 1 and Comparative Example 1 after being immersed in a 3.5% by mass NaCl solution at room temperature for 24 hours after the corrosion products are removed are shown in the attached figures. Figure 5 and attached Figure 6 As shown. Figure 5 and attached Figure 6 It can be seen that the corrosion marks of the magnesium alloy described in Example 1 are much smaller than those of the magnesium alloy in Comparative Example 1.

[0073] The test results of elongation and corrosion rate of each group of magnesium alloys in Examples 1 to 12 and Comparative Examples 1 to 13 are shown in Table 4.

[0074] Table 4 Mechanical and corrosion properties test results of magnesium alloys of Examples 1 to 12 and Comparative Examples 1 to 13

[0075]

[0076]

[0077] As can be seen from the results in Table 4, the magnesium alloys described in Examples 1 to 12 of the present invention all have relatively good mechanical properties, with elongations reaching more than 15%, which can meet conventional processing requirements. At the same time, the corrosion rate is below 0.3 mm / year, and the corrosion resistance is significantly better than that of Comparative Examples 1 to 13.

[0078] Comparing Comparative Examples 1 to 3 with Examples 1 to 3, respectively, the magnesium alloy lacks one of Sn, Al, Zr, and Mn. By comparing Comparative Examples 1 to 3 with Examples 1 to 3, it can be seen that the lack of Sn regulates plasticity, Al and Zr reduce the grain size and improve the corrosion performance of the matrix, and Mn reduces the Fe impurity content of the matrix, and the comprehensive performance of the alloy is significantly reduced.

[0079] Compared with Example 1, the main difference between Comparative Examples 4 and 5 is the different Sn content. The Sn content in Comparative Example 4 is too small, and the magnesium alloy described in Comparative Example 4 has the problem that the Sn content is too small to regulate the mechanical properties; the Sn content in Comparative Example 5 is too high, and the magnesium alloy described in Comparative Example 5 has the problem of micro galvanic corrosion spacing.

[0080] Compared with Example 1, the main differences between Comparative Examples 6 to 9 are that the contents of Al and Zr are different or only one of Al and Zr is contained. The Al and Zr contents contained in Comparative Example 6 are relatively small, and the magnesium alloy described in Comparative Example 6 has the problem that the Al and Zr contents are too small to improve the performance; the Al and Zr contents contained in Comparative Example 7 are too large, and the magnesium alloy described in Comparative Example 7 has the problem that the precipitation phase is generated and the corrosion performance is worsened; Comparative Example 8 contains only Al, and the magnesium alloy described in Comparative Example 8 has the problem of lacking the co-reaction effect of Zr and cannot effectively improve the mechanics and corrosion; Comparative Example 9 contains only Zr, and the magnesium alloy described in Comparative Example 9 has the problem of lacking the co-reaction effect of Al and cannot effectively improve the mechanics and corrosion.

[0081] Compared with Example 1, the main difference between Comparative Examples 10 and 11 is the different Mn content. The Mn content in Comparative Example 10 is too little, and the magnesium alloy described in Comparative Example 10 has a problem of significantly increased impurity Fe content, which affects the corrosion resistance of the magnesium alloy; the Mn content in Comparative Example 11 is too much, and the magnesium alloy described in Comparative Example 11 has a problem of causing precipitation phase formation and causing severe microgalvanic corrosion.

[0082] Compared with Example 1, Comparative Example 12 uses an equal amount of Gd to replace Sn. The magnesium alloy obtained in Comparative Example 12 has the problems of increased corrosion rate and decreased plasticity.

[0083] Compared with Example 1, Comparative Example 13 uses an equal amount of Ca to replace Mn. The Ca in the magnesium alloy of Comparative Example 13 cannot effectively reduce the content of impurity Fe in the magnesium alloy, and there is a problem that the corrosion rate and mechanics are not as good as those of Example 1.

[0084] 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 the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high plasticity and high corrosion resistance magnesium alloy, characterized in that: The magnesium alloy comprises the following components in percentage by weight: Sn 1-6%, Al 0.1-1%, Zr 0.1-1%, Mn 0.01-3%, and the balance being Mg and unavoidable impurities; The unavoidable impurities include Fe, and the weight percentage of Fe in the magnesium alloy is not higher than 0.05%; Wherein, the mass ratio of Al to Zr is 1:1; The magnesium alloy has an elongation of 15% or more, and a corrosion rate of less than 0.3 mm / year in a 3.5% by mass NaCl solution. The method for preparing the high-plasticity and high-corrosion-resistant magnesium alloy comprises the following steps: (1) Homogenization treatment: weigh the raw materials of each component according to the composition ratio of the magnesium alloy to prepare a magnesium ingot, and perform homogenization treatment on the prepared magnesium ingot at a treatment temperature of 500-550°C and a treatment time of 4-10 hours; (2) Extrusion treatment: the raw material after homogenization treatment in step (1) is extruded at an extrusion temperature of 300-340°C and an extrusion ratio of (3-18):1; (3) Heat treatment: The alloy obtained by extrusion in step (2) is subjected to heat treatment at a temperature of 150-200°C for a time of 10-40 minutes, and a high-plasticity and high-corrosion-resistant magnesium alloy is obtained after the treatment.

2. The high plasticity and high corrosion resistant magnesium alloy according to claim 1, characterized in that: The weight percentage of Sn in the magnesium alloy is 1-2%.

3. The high plasticity and high corrosion resistant magnesium alloy according to claim 1, characterized in that: The weight percentages of Al and Zr in the magnesium alloy are both 0.1-0.5%.

4. The high plasticity and high corrosion resistant magnesium alloy according to claim 1, characterized in that: The weight percentage of Mn in the magnesium alloy is 1-2%.

5. A method for preparing a high-plasticity and high-corrosion-resistant magnesium alloy according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: (1) Homogenization treatment: weigh the raw materials of each component according to the composition ratio of the magnesium alloy to prepare a magnesium ingot, and perform homogenization treatment on the prepared magnesium ingot at a treatment temperature of 500-550°C and a treatment time of 4-10 hours; (2) Extrusion treatment: the raw material after homogenization treatment in step (1) is extruded at an extrusion temperature of 300-340°C and an extrusion ratio of (3-18):1; (3) Heat treatment: The alloy obtained by extrusion in step (2) is subjected to heat treatment at a temperature of 150-200°C for a time of 10-40 minutes, and a high-plasticity and high-corrosion-resistant magnesium alloy is obtained after the treatment.

6. The method for preparing a high-plasticity and high-corrosion-resistant magnesium alloy according to claim 5, wherein: The preparation method satisfies at least one of the following conditions: (a) The homogenization treatment temperature in step (1) is 530° C. and the treatment time is 8 hours; (b) the extrusion temperature in step (2) is 320° C. and the extrusion ratio is 6:1; (c) In step (3), the heat treatment temperature is 180° C. and the treatment time is 30 minutes.

7. Use of the high-plasticity and high-corrosion-resistant magnesium alloy according to any one of claims 1 to 4 in 3C products, automobiles, and ships.

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