High plasticity heat-conducting deformed magnesium alloy, and preparation method and application thereof

Abstract

The application provides a high-plasticity heat-conducting deformed magnesium alloy and a preparation method and application thereof, and relates to the technical field of heat-conducting magnesium alloys.The high-plasticity heat-conducting deformed magnesium alloy provided by the application contains, in percentage by mass, 1.45-1.55% of Zn, 0.45-0.55% of Mn, 0.45-0.55% of RE, 0.1-0.5% of Ca and the balance of Mg; wherein the RE is a mixture of La and Ce, and the mass fraction of La in the RE is 32-34%. The high-plasticity heat-conducting deformed magnesium alloy provided by the application has a room-temperature thermal conductivity of greater than or equal to 126 W / (m*K), a tensile strength of greater than or equal to 243 MPa and an elongation of greater than or equal to 22%. The addition of Mg-30wt.% RE can improve the strength and heat-conducting performance of the Mg-Zn-Mn alloy, the addition of Ca can significantly improve the plasticity of the Mg-1.5Zn-0.5Mn-0.5RE alloy, and the mixed rare earth has a lower cost than the binary rare earth intermediate alloy and the rare earth metal.

Description

Technical Field

[0001] This invention relates to the technical field of thermally conductive magnesium alloys, and more particularly to a high-plasticity thermally conductive deformable magnesium alloy, its preparation method, and its applications. Background Technology

[0002] Magnesium is one of the lightest metallic structural materials ever discovered, with a density of only 1.74 g / cm³. 3 Magnesium has a thermal conductivity of only 2 / 3 that of aluminum and 1 / 4 that of iron. Therefore, in the context of carbon peaking and carbon neutrality, the application of magnesium alloys contributes to lightweighting and energy conservation and emission reduction, and is hailed as a "green engineering material of the 21st century." Pure magnesium has a thermal conductivity of 156 W / (m·K), second only to copper and aluminum among commonly used metallic structural materials. However, pure magnesium has poor mechanical properties, with a yield strength of only 21 MPa, which is insufficient to meet practical application requirements.

[0003] Therefore, magnesium is often used in the form of magnesium alloys. Alloying magnesium can effectively improve its mechanical properties, but it can negatively affect its thermal conductivity. For example, the commercial magnesium alloy AM60B has a tensile strength of up to 225 MPa, but its thermal conductivity drops to 60 W / (m·K). Another commercial magnesium alloy, AZ91D, has a tensile strength exceeding 240 MPa, but its thermal conductivity drops to 53 W / (m·K). This illustrates that the thermal conductivity and mechanical properties of magnesium alloys are often contradictory.

[0004] Magnesium alloys can be classified into cast magnesium alloys and wrought magnesium alloys based on their forming process. It is more difficult to achieve both high thermal conductivity and good mechanical properties in cast magnesium alloys. For example, the die-cast magnesium alloy Mg-0.7Si-0.4Sn-0.3Ca provided by Chinese invention patent CN115679172A has a room temperature thermal conductivity as high as 144.5 W / (m·K), but a tensile strength of only 107.2 MPa and an elongation of 9.7%. Conversely, the die-cast magnesium alloy Mg-6Al-5.5Zn-3RE-Y provided by Chinese invention patent CN115874097A has a yield strength of 157 MPa and a tensile strength of 250 MPa, but its thermal conductivity is only 90.3 W / (m·K). Therefore, in order to balance thermal conductivity and strength, cast thermally conductive magnesium alloys are usually designed with complex compositions. For example, the Mg-3.92Al-3.11La-1.55Sm-0.23Y-0.09Te alloy provided by Chinese invention patent CN116254446A has a room temperature thermal conductivity of 171 W / (m·K), a yield strength of 198 MPa, a tensile strength of 287 MPa, and an elongation of 7.2%.

[0005] Compared to cast magnesium alloys, wrought magnesium alloys, through subsequent processing, can effectively refine grains, control texture, eliminate defects in the magnesium alloy, and significantly improve mechanical properties, while having no significant impact on thermal conductivity, thus obtaining high-strength and high-thermal-conductivity magnesium alloys. For example, the thermally conductive wrought magnesium alloy Mg-2.8Al-5.0La-0.3Mn provided by Chinese invention patent CN113322404A has a room temperature thermal conductivity of 119 W / (m·K), a tensile strength of 332.2 MPa, a yield strength of 271.0 MPa, and an elongation of 10.8%, but it still does not reach high plasticity.

[0006] Generally speaking, magnesium alloys with an elongation of less than 15% are considered ordinary plastic wrought magnesium alloys. To obtain high plastic wrought magnesium alloys with an elongation of more than 15%, more complex processes are often required. For example, the high plastic magnesium alloy provided by Chinese invention patent CN115233061A undergoes a two-stage solution treatment process of 400℃ / 3h + 530℃ / 6h → forging at 350℃ → extrusion at 350℃ → preheating at 300℃ followed by multi-path temperature rolling at 250℃ → aging at 195℃ / 5-15h. The resulting Mg-2Gd-2Nd-0.3Ce-0.6Zr has a tensile strength higher than 190MPa, a yield strength higher than 150MPa, and an elongation higher than 30%. However, the heat treatment process is complicated and not suitable for large-scale industrial production.

[0007] The plasticity of wrought magnesium alloys significantly affects their application range. For example, the elongation of commercial magnesium alloy ZK61M in the T6 condition is less than 14%, which greatly limits its application in aerospace, automotive, and structural materials industries. Similarly, the elongation of wrought magnesium alloy Mg-1Al-0.4Ca-0.5Mn-0.2Zn is less than 13% under different extrusion temperatures, limiting its application to casings and covers, computer components, etc., where plasticity requirements are not high. However, if the elongation exceeds 20%, the application range of wrought magnesium alloys expands significantly. For instance, WE54 and WE43 in the WE series (Mg-Y-Nd-RE) alloys can achieve elongations of over 20%, and have already found mature applications in my country's aerospace, transportation, and missile manufacturing sectors.

[0008] In summary, in order to improve the defects of the thermally conductive magnesium alloys provided in the prior art, the present invention provides a wrought magnesium alloy with high plasticity and high thermal conductivity. Summary of the Invention

[0009] The purpose of this invention is to provide a high-plasticity thermally conductive deformable magnesium alloy, its preparation method, and its application.

[0010] In a first aspect, the present invention provides a high-ductility thermally conductive deformable magnesium alloy, comprising, by mass percentage: 1.45-1.55% Zn, 0.45-0.55% Mn, 0.45-0.55% RE, 0.1-0.5% Ca, and the balance Mg; wherein the RE is a mixture of La and Ce, and the mass fraction of La in the RE is 32-34%.

[0011] The high-ductility thermally conductive deformable magnesium alloy provided by this invention improves the overall strength and thermal conductivity of the magnesium alloy by adding trace amounts of RE elements. At the same time, by controlling the content of Ca elements, the magnesium alloy grains are refined, thereby improving the coarse structure of the magnesium alloy and regulating the type, morphology and size of the second phase, which greatly improves the plasticity of the magnesium alloy. The resulting magnesium alloy has a room temperature thermal conductivity greater than or equal to 126 W / (m·K), a tensile strength greater than or equal to 243 MPa and an elongation greater than or equal to 22%.

[0012] Secondly, the present invention provides a method for preparing the above-mentioned high-plasticity thermally conductive deformable magnesium alloy, comprising the following steps:

[0013] Pure Mg, pure Zn, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy were weighed and mixed according to the mass ratio; wherein, in the Mg-30wt.%RE master alloy, RE is a mixture of La and Ce, and the mass fraction of La in RE is 32-34%;

[0014] Under a protective atmosphere, pure Mg is heated to the point of melting, and then pure Zn is added and stirred until melted. Then, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are added in sequence and stirred until melted to obtain an alloy melt.

[0015] Under an inert atmosphere, a refining agent is added to the alloy melt and stirred for 5-10 minutes. A covering agent is then spread on the surface, and the melt is kept warm before slag removal. The alloy ingot is then cooled in a mold to obtain an alloy casting. The alloy ingot is gradually heated to 410-420℃ and kept at that temperature for 11-13 hours before cooling. It is then extruded at 355-365℃ to obtain a high-plasticity thermally conductive deformable magnesium alloy.

[0016] Optionally, pure Mg, pure Zn, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are weighed and mixed according to mass ratio, and then the pure Mg, pure Zn, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are dried and preheated in a vacuum environment at 100-150°C.

[0017] Optionally, during the process of heating pure Mg to the point of melting under a protective atmosphere, the protective atmosphere is a mixture of SF6 and CO2, and the volume ratio of SF6 in the protective atmosphere is 0.9-1.1%.

[0018] Optionally, the process of heating pure Mg to melt under a protective atmosphere includes: spreading a covering agent on the surface of pure Mg at 390-410°C and then uniformly heating until the pure Mg is completely melted.

[0019] Optionally, in the process of heating pure Mg to molten state under a protective atmosphere, adding pure Zn and stirring to melt, and then sequentially adding Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy, and Mg-30wt.%RE master alloy and stirring to melt, the process for obtaining the alloy melt includes:

[0020] Molten Mg is heated to 715-725℃, and pure Zn is added and stirred to melt, thus obtaining a Mg-Zn mixed melt.

[0021] The Mg-Zn mixed melt is heated to 745-755℃, and Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are added in sequence. After stirring for 3-5 minutes, a covering agent is spread on the surface and the mixture is kept at the temperature until it is completely melted to obtain the alloy melt.

[0022] Thirdly, the present invention also provides applications of the high-ductility thermally conductive deformable magnesium alloys prepared by any of the above-described methods. Specifically, they can be applied in the fields of aerospace, transportation, and missile manufacturing. Attached Figure Description

[0023] Figure 1 A flowchart illustrating a method for preparing a high-ductility, thermally conductive, deformable magnesium alloy, as provided in an embodiment of the present invention;

[0024] Figure 2 Microstructure diagrams of the high-plasticity thermally conductive deformable magnesium alloys prepared in Examples 1-3 and Comparative Examples 1-3;

[0025] Figure 3 X-ray diffraction analysis results of the high-plasticity thermally conductive deformable magnesium alloys prepared in Example 2 and Comparative Examples 1-3;

[0026] Figure 4 The tensile curves are those of the high-plasticity thermally conductive deformable magnesium alloys prepared in Example 2 and Comparative Examples 1-3. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0028] See Figure 1 This invention provides a method for preparing a high-ductility, thermally conductive deformable magnesium alloy, comprising the following steps:

[0029] S1. Weighing and batching: Weigh pure Mg, pure Zn, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy according to the mass ratio and batch them;

[0030] S2. Alloy smelting: Under a protective atmosphere, pure Mg is heated to the point of melting, then pure Zn is added and stirred until melted. Then, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are added sequentially and stirred until melted to obtain an alloy melt. Under an inert atmosphere, a refining agent is added to the alloy melt and stirred for 5-10 minutes. A covering agent is then spread on the surface of the melt, and after heat preservation, the slag is removed.

[0031] S3, casting: Cool to 710℃ and cast into a preheated mold, then air cool to obtain an alloy ingot;

[0032] S4. Extrusion molding: The alloy ingot is gradually heated to 410-420℃ and held for 11-13 hours, then cooled and extruded at 355-365℃ to obtain a high-plasticity thermally conductive deformable magnesium alloy.

[0033] It should be noted that when performing step S1, Mg-10wt.%Mn master alloy means that the mass fraction of Mn in the Mg-Mn alloy is 10%, Mg-20wt.%Ca master alloy means that the mass fraction of Ca in the Mg-Ca alloy is 20%, and Mg-30wt.%RE master alloy means that the mass fraction of RE in the Mg-RE alloy is 30%.

[0034] In practice, when performing step S1, the raw materials can be weighed and batched in a mass ratio of Mn-1.5Zn-0.5Mn-0.5RE-0.1Ca. Since melting losses are inevitable during the alloy melting process, a margin needs to be allowed when weighing. Specifically, the raw materials used for weighing and batching are all commercially available conventional products.

[0035] Specifically, in step S1, the selected Mg-30wt.%RE master alloy contains a mixture of La and Ce, with La accounting for 32-34% of the mass fraction in the RE. Therefore, after the alloy smelting process, the mass fraction of La to Ce in the resulting high-ductility thermally conductive deformable magnesium alloy is approximately 1:2.

[0036] In some embodiments, after performing step S1, the weighed raw materials can be dried and preheated in a vacuum environment at 100-150°C. In practice, the raw materials can also be pre-cleaned, which helps to improve the cleanliness of the raw materials and thus reduce the impact of impurities on the magnesium alloy melt during alloy smelting.

[0037] In some embodiments, during the process of heating pure Mg to the point of melting in a protective atmosphere in step S2, the selected protective atmosphere is a mixture of SF6 and CO2, wherein the volume ratio of SF6 in the protective atmosphere is 0.9-1.1.

[0038] In some embodiments, the process of heating pure Mg to melt under a protective atmosphere in step S2 includes: heating pure Mg to 390-410°C under a protective atmosphere, then spreading a covering agent on the surface of the pure Mg and uniformly heating until the pure Mg is completely melted. Specifically, pure Mg can be completely dissolved when heated to above 700°C, and the covering agent spread on the surface of the pure Mg is also included.

[0039] In some embodiments, step S2 further includes:

[0040] Molten Mg is heated to 715-725℃, and pure Zn is added and stirred to melt, thus obtaining a Mg-Zn mixed melt.

[0041] After heating the Mg-Zn mixed melt to 745-755℃, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are added in sequence. After stirring for 3-5 minutes, a covering agent is spread on the surface of the melt and kept at the temperature until it is completely melted to obtain the alloy melt.

[0042] In some embodiments, when performing step S2, when adding a refining agent to the alloy melt under an inert atmosphere, the inert atmosphere may specifically be an argon atmosphere, and the refining agent may specifically be an RJ-5 refining agent, and the amount of refining agent added may be 2% of the mass of the alloy melt.

[0043] Specifically, when the refining agent is added to the alloy melt and stirred in step S2, a mirror-like luster can be achieved on the surface of the alloy melt.

[0044] Specifically, in step S2, after spreading the covering agent on the surface of the melt for heat preservation and then removing the slag, the surface of the melt can be removed after heat preservation at 750°C for 20 minutes. Then, in step S3, the melt is cooled to 710°C and poured into a preheated mold for air cooling to form an alloy ingot.

[0045] In fact, the high-ductility thermally conductive deformable magnesium alloy prepared by the preparation method provided in the embodiments of the present invention comprises, by mass percentage, 1.45-1.55% Zn, 0.45-0.55% Mn, 0.45-0.55% RE, 0.1-0.5% Ca and the balance Mg; wherein the RE is a mixture of La and Ce, and the mass fraction of La in the RE is 32-34%.

[0046] Example 1

[0047] This embodiment 1 provides a method for preparing a high-ductility, thermally conductive, deformable magnesium alloy, comprising the following steps:

[0048] S1. Weighing and Batching: Weigh pure Mg, pure Zn, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy according to the mass ratio of Mg-1.5Zn-0.5Mn-0.5RE-0.1Ca, and then dry and preheat them in a vacuum drying oven at 130℃; wherein, RE in Mg-30wt.%RE master alloy is a mixture of La and Ce in a mass ratio of 1:2;

[0049] S2. Alloy Melting: After heating the crucible to 400℃, a protective atmosphere is introduced. Pure Mg is placed in the crucible, and a covering agent is spread on the surface of the pure Mg. The temperature is then uniformly raised to above 700℃ until the pure Mg is completely melted. The temperature is further raised to 720℃, and pure Zn is added and stirred until completely melted. The temperature is further raised to 750℃, and Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy, and Mg-30wt.%RE master alloy are added in sequence. The melt is stirred for 3 minutes, and a covering agent is spread on the surface of the melt and kept at the temperature until completely melted to obtain an alloy melt. Under an argon atmosphere, 2% of the alloy melt mass of RJ-5 refining agent is added to the crucible. The mixture is mechanically stirred for 5-10 minutes until the surface of the melt has a mirror-like luster. The slag on the surface of the melt is removed and a covering agent is spread on it. The mixture is kept at 750℃ for 20 minutes and then the slag is skimmed off.

[0050] S3, Casting: Cool to 710℃ and cast into a preheated mold, then air cool to obtain an alloy ingot;

[0051] S4. Extrusion molding: The alloy ingot is placed in a box-type resistance furnace and heated to 415℃ and held for 12 hours. After the alloy ingot is removed and air-cooled to room temperature, the surface oxide scale is removed. The alloy ingot is preheated to 360℃ and extruded at 360℃ with an extrusion ratio of 25:1 and an extrusion speed of 2mm / s to obtain high-plasticity thermally conductive deformable magnesium alloy rods.

[0052] Example 2

[0053] This embodiment 2 provides a method for preparing a high-plasticity thermally conductive deformable magnesium alloy. The difference from embodiment 1 is that in step S1, the ingredients are weighed according to the mass ratio of Mg-1.5Zn-0.5Mn-0.5RE-0.3Ca.

[0054] Example 3

[0055] This embodiment 3 provides a method for preparing a high-plasticity thermally conductive deformable magnesium alloy. The difference from embodiment 1 is that in step S1, the ingredients are weighed according to the mass ratio of Mg-1.5Zn-0.5Mn-0.5RE-0.5Ca.

[0056] Comparative Example 1

[0057] Comparative Example 1 provides a method for preparing a high-plasticity thermally conductive deformable magnesium alloy. The difference from Example 1 is that in step S1, pure Mg, pure Zn, and Mg-10wt.%Mn master alloy are weighed according to the mass ratio of Mg-1.5Zn-0.5Mn, and in step S2, Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are not added.

[0058] Comparative Example 2

[0059] Comparative Example 2 provides a method for preparing a high-plasticity thermally conductive deformable magnesium alloy. The difference from Example 1 is that in step S1, pure Mg, pure Zn, Mg-10wt.%Mn master alloy, Mg-20wt.%Ca master alloy and Mg-30wt.%La master alloy are weighed according to the mass ratio of Mg-1.5Zn-0.5Mn-0.5La. In step S2, Mg-30wt.%La master alloy is added, but Mg-20wt.%Ca master alloy and Mg-30wt.%RE master alloy are not added.

[0060] Comparative Example 3

[0061] Comparative Example 3 provides a method for preparing a high-plasticity thermally conductive deformable magnesium alloy. The difference from Example 1 is that in step S1, pure Mg, pure Zn, Mg-10wt.%Mn master alloy and Mg-30wt.%RE master alloy are weighed according to the mass ratio of Mg-1.5Zn-0.5Mn-0.5RE, and Mg-20wt.%Ca master alloy is not added in step S2.

[0062] Performance testing and data

[0063] The high-ductility thermally conductive deformable magnesium alloy bars prepared in Examples 1-3 and Comparative Examples 1-3 were tested for the following items:

[0064] Composition determination: According to GB / T 13748-2005 "Methods for Chemical Analysis of Magnesium and Magnesium Alloys", samples were taken and the composition was tested using an electric spark direct reading spectrometer and an ICP (Inductive Coupled Plasma Emission Spectrometer). The results are shown in Table 1.

[0065] Room temperature thermal conductivity: The thermal conductivity was measured using a laser thermal conductivity meter (LFA457) according to the method specified in GB / T22588-2008 "Measuring thermal diffusivity or thermal conductivity by flash method". The results are shown in Table 2.

[0066] Room temperature mechanical properties: The processing and testing were carried out in accordance with GB6397-86 "Metallic materials - Tensile test specimens". The testing equipment was a Labsans 30kN universal testing machine tensile tester. The specific test items were tensile strength, yield strength and elongation. The results are shown in Table 2.

[0067] Table 1 shows the measured composition of magnesium alloys in Examples 1-3 and Comparative Examples 1-3.

[0068]

[0069] Table 2 Thermal conductivity and mechanical properties of the examples

[0070]

[0071] from Figures 2 to 4 As can be seen from Table 2, the addition of Ca can weaken the traditional basal texture of extruded magnesium alloys and form a texture parallel to the extrusion direction. At the same time, the synergistic strengthening of RE and Ca can improve the morphology and distribution of the second phase of magnesium alloys. Furthermore, after extrusion, it can exhibit excellent grain refinement and dispersion strengthening effects. Compared with adding RE alone, it greatly improves the plasticity of the alloy and better balances thermal conductivity and mechanical properties.

[0072] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A method for preparing a high-ductility, thermally conductive, deformable magnesium alloy, characterized in that, Includes the following steps: Pure Mg, pure Zn, Mg-10 wt.%Mn master alloy, Mg-20 wt.%Ca master alloy and Mg-30 wt.%RE master alloy were weighed and mixed according to the mass ratio; wherein, in the Mg-30 wt.%RE master alloy, RE is a mixture of La and Ce; Under a protective atmosphere, pure Mg was heated to melt, and then pure Zn was added and stirred until melted. Then, Mg-10 wt.%Mn master alloy, Mg-20 wt.%Ca master alloy and Mg-30 wt.%RE master alloy were added in sequence and stirred until melted to obtain an alloy melt. Under an inert atmosphere, a refining agent is added to the alloy melt and stirred for 5-10 minutes. A covering agent is then spread on the surface, and after heat preservation, slag is removed. The alloy ingot is then cooled in a mold to obtain an alloy ingot. The alloy ingot is gradually heated to 410-420℃ and held for 11-13 hours before cooling. It is then extruded at 355-365℃ to obtain a high-plasticity thermally conductive wrought magnesium alloy. The high-plasticity thermally conductive wrought magnesium alloy comprises, by mass percentage: 1.45-1.55% Zn, 0.45-0.55% Mn, 0.45-0.55% RE, 0.1-0.5% Ca, and the balance Mg. The RE is a mixture of La and Ce, and the mass fraction of La in the RE is 32-34%.

2. The preparation method according to claim 1, characterized in that, The high-plasticity thermally conductive deformable magnesium alloy has a room temperature thermal conductivity greater than or equal to 126 W / (m·K), a tensile strength greater than or equal to 243 MPa, and an elongation greater than or equal to 22%.

3. The preparation method according to claim 1, characterized in that, Pure Mg, pure Zn, Mg-10 wt.%Mn master alloy, Mg-20 wt.%Ca master alloy, and Mg-30 wt.%RE master alloy were weighed and mixed according to the mass ratio. Then, the pure Mg, pure Zn, Mg-10 wt.%Mn master alloy, Mg-20 wt.%Ca master alloy, and Mg-30 wt.%RE master alloy were dried and preheated in a vacuum environment at 100-150℃.

4. The preparation method according to claim 1, characterized in that, During the process of heating pure Mg to the point of melting under a protective atmosphere, the protective atmosphere is a mixture of SF6 and CO2, and the volume ratio of SF6 in the protective atmosphere is 0.9-1.1%.

5. The preparation method according to claim 1, characterized in that, The process of heating pure Mg to the point of melting under a protective atmosphere includes: spreading a covering agent on the surface of pure Mg at 390-410℃ and then uniformly heating until the pure Mg is completely melted.

6. The preparation method according to claim 1, characterized in that, Pure Mg is heated to molten state under a protective atmosphere, then pure Zn is added and stirred until melted. Subsequently, Mg-10 wt.%Mn master alloy, Mg-20 wt.%Ca master alloy, and Mg-30 wt.%RE master alloy are added sequentially and stirred until melted. The process of obtaining the alloy melt includes: Molten Mg is heated to 715-725℃, and pure Zn is added and stirred to melt, thus obtaining a Mg-Zn mixed melt. The Mg-Zn mixed melt is heated to 745-755℃, and Mg-10 wt.%Mn master alloy, Mg-20 wt.%Ca master alloy and Mg-30 wt.%RE master alloy are added in sequence. After stirring for 3-5 minutes, a covering agent is spread on the surface and the mixture is kept at the temperature until it is completely melted to obtain the alloy melt.

7. The application of a high-ductility thermally conductive deformable magnesium alloy prepared by the preparation method according to any one of claims 1 to 6 in the fields of aerospace, transportation, and missile manufacturing.

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