A method for preparing Mg-Al-Ta layered composite metal plate by hot-dip plating and vacuum diffusion bonding

Abstract

The present application relates to a kind of Mg-Al-Ta layered composite metal plate hot-dip plating+vacuum diffusion connection combined preparation method.Solve the technical problems of the present Mg-Al-Ta layered composite metal plate preparation process production efficiency is not high, and the interface bonding capacity of the poor technical problem existing in the preparation of Mg-Al-Ta dissimilar metal composite plate using conventional processing means.The preparation method of the present application, first to the surface of several pure Ta plate material hot-dip aluminum, then several deformed Mg alloy plate and several plated Ta plate are alternately stacked in sequence, vacuum diffusion connection, obtain Mg-Al-Ta layered composite metal plate.The preparation method is high in efficiency, low in cost, suitable for the preparation of large-area Mg-Al-Ta layered composite metal plate, the composite metal plate prepared has high strength, size and strong quality stability, especially suitable for the processing and manufacturing of radiation-resistant lightweight layered composite material for deep space probe shielding structure.

Description

Technical Field

[0001] This invention belongs to the field of materials forming technology, specifically relating to a method for preparing Mg-Al-Ta layered composite metal sheets by hot-dip galvanizing and vacuum diffusion bonding. Background Technology

[0002] Deep space exploration is a crucial indicator of a nation's comprehensive national strength and innovation capabilities. Conducting and continuously advancing deep space exploration is of great significance for safeguarding national security, promoting scientific and technological progress, enhancing national soft power, and increasing international influence. However, the high-energy charged particles present in the deep space environment have extremely strong penetrating power and can easily trigger space electron radiation, damaging electronic components within spacecraft and affecting exploration missions. This poses a significant challenge to the resistance of materials used in probe equipment to high-energy particle radiation. High-Z (atomic number) metals such as niobium and tantalum possess excellent electron shielding effects and have been successfully used by NASA as high-energy electron shielding materials on the Juno Jupiter probe. However, due to the increasing distance of deep space exploration and the limitations of current spacecraft launch capabilities, lightweight design of materials used in probe equipment is crucial for promoting the development of deep space exploration. Analysis and calculation results regarding radiation-resistant material systems show that, at the same areal density, an optimized combination of low-Z (e.g., Mg) and high-Z (Ta) materials can achieve better shielding effects than a single high-Z material, while effectively reducing weight. However, due to the significant differences in the physicochemical properties of Mg and Ta, it is difficult to obtain composite plates with high interfacial bonding strength (the yield strength of the Mg / Ta interface must be >100MPa) through traditional processing methods. Since Al and Ta both have a BCC structure and are somewhat miscible, and Al and Mg elements have excellent miscibility, Al can be used as a medium to connect Mg and Ta, enabling the preparation of Mg / Al / Ta metal composite materials.

[0003] In the prior art, regarding the preparation and forming of Mg-Al-Ta layered composite metal sheets, publication number CN113733685... Chinese patent A discloses a lightweight, high-strength Mg-Al-Ta composite metal sheet and its rolling forming method. Although this method can obtain a shaped Mg / Al / Ta composite sheet, the optimal hot working temperature ranges of Mg, Al, and Ta metals are significantly different, making it difficult to achieve coordinated deformation under the same temperature conditions. Therefore, the process usually involves heat preservation treatment of Mg sheet and pure Ta sheet at different temperatures, and then stacking and fixing the sheets. The temperature change of the stacked sheets before rolling deformation is difficult to control effectively, and the production efficiency is low. At the same time, the oxidation problem of the sheet during heating is difficult to control. Chinese patent CN116372344A discloses a hot isostatic pressing diffusion bonding method for preparing Mg / Al / Ta layered composite metal sheets. Although it can realize the processing and preparation of Mg / Al / Ta composite sheets, the process involves surface roughening of Ta sheet and aluminizing by magnetron sputtering. The process is relatively complex, with high requirements for coating equipment, hot isostatic pressing equipment and process parameters, and low production efficiency. Furthermore, the Mg / Al / Ta composite plates prepared by the above method have a narrow interfacial diffusion layer due to temperature limitations, and no obvious metallurgical bond is formed between the dissimilar metal layers, which is not ideal for the interfacial bonding strength of the composite plates. Summary of the Invention

[0004] The purpose of this invention is to address the low production efficiency of existing Mg-Al-Ta layered composite metal sheet preparation processes and the poor interfacial bonding ability in Mg-Al-Ta dissimilar metal composite sheets prepared using conventional processing methods. This invention provides a combined hot-dip galvanizing and vacuum diffusion bonding method for preparing Mg-Al-Ta layered composite metal sheets, which enables strong metallurgical bonding at the interface, resulting in Mg-Al-Ta layered composite metal sheets with excellent interfacial bonding, thereby further promoting the engineering application of this type of composite sheet.

[0005] The technical solution adopted by the present invention to achieve the above objectives is as follows.

[0006] This invention provides a method for preparing Mg-Al-Ta layered composite metal sheets by hot-dip galvanizing and vacuum diffusion bonding, comprising the following steps:

[0007] Step 1: Polish, clean, and vacuum dry the pure Ta plates and pure Al blocks to remove surface oil and oxide layers, and obtain cleaned pure Ta plates and pure Al blocks.

[0008] Step 2: Under a protective atmosphere, melt the cleaned pure Al block to obtain molten Al liquid;

[0009] Step 3: Immerse the cleaned pure Ta plate into molten Al liquid, remove and cool to complete the surface hot-dip aluminizing process, and obtain aluminized Ta plate;

[0010] Step 4: After surface polishing, cleaning, and vacuum drying of several aluminum-plated Ta plates and several deformed Mg alloy plates, they are stacked alternately to obtain a multi-layer structure plate.

[0011] Step 5: Vacuum diffusion bonding of the multi-layer structured plates to obtain Mg-Al-Ta layered composite metal plates.

[0012] Preferably, in step one, the purity of the pure Ta plate is ≥99.99%, and the purity of the pure Al block is ≥99.6%.

[0013] Preferably, in step one, the pure Al block and pure Ta plate are polished with an angle grinder and wire brush, and the cleaning is performed by ultrasonic cleaning in anhydrous ethanol for 5-10 minutes. The vacuum drying temperature is 50℃-100℃.

[0014] Preferably, in step two, the cleaned pure Al block is placed in an induction furnace filled with nitrogen for melting; the melting temperature of the cleaned pure Al block is controlled at 750℃-850℃; and the surface slag of the molten Al liquid is removed after melting.

[0015] Preferably, in step three, the conditions for the hot-dip aluminizing process are: carried out under a protective atmosphere, the temperature of the molten Al liquid is 750℃-850℃, and the immersion time is 5min-30min, more preferably 5min-20min, and especially preferably 16min-18min.

[0016] Preferably, in step three, the cleaned pure Ta plate is immersed in molten Al liquid using a vertical suspension method.

[0017] Preferably, in step four, the deformed Mg alloy sheet is AZ31 wrought magnesium alloy sheet or EW75 wrought magnesium alloy sheet, with a deformation amount of 20%-60%.

[0018] Preferably, in step four, the aluminum-plated Ta plate and the deformed Mg alloy plate are polished with an angle grinder and a wire brush; the cleaning is performed by ultrasonic cleaning in anhydrous ethanol for 5-10 minutes; and the vacuum drying temperature is 50℃-100℃.

[0019] Preferably, in step four, there are N aluminum-plated Ta plates and N+1 deformed Mg alloy plates, where N≥1, and the top and bottom layers of the multi-layer structure plate are both deformed Mg alloy plates; more preferably, N=1, and the deformed Mg alloy plates, aluminum-plated Ta plates, and deformed Mg alloy plates are stacked sequentially.

[0020] Preferably, in step five, the vacuum diffusion bonding process conditions are: vacuum degree below 10 Pa, pressure 15 MPa-50 MPa, temperature (0.6-0.8) × 650 °C (the melting point of Mg), and time above 1 hour; more preferably, 1-2 hours.

[0021] The principle of this invention is as follows: The method for preparing Mg-Al-Ta layered composite metal plates by hot-dip galvanizing and vacuum diffusion bonding involves first placing a pure Ta plate in molten Al and performing a hot-dip aluminum plating process (temperature: 750℃-850℃, time: 5min-30min) to achieve metallurgical bonding between the pure Al and pure Ta plates. The hot-dip plating method under a protective atmosphere effectively avoids the oxidation problem on the surface of the pure Ta plate. At the same time, the hot-dip plating under high temperature and for an appropriate time can effectively promote the mutual diffusion of atoms at the Al / Ta interface, forming a strong metallurgical bonding interface. Meanwhile, the hot-dip aluminum plating layer can serve as an effective medium for subsequent bonding of Mg alloy plates and pure Ta plates. Secondly, the vacuum diffusion bonding process (vacuum degree below 10 Pa, pressure 15-50 MPa, temperature (0.6-0.8) × 650℃ of Mg melting point, time above 1 hour) enables a good metallurgical bond between the modified Mg alloy plate and the aluminum coating layer on the Ta plate surface. Furthermore, the use of a modified magnesium alloy plate increases the diffusion channels at the Mg / Al interface, further promoting vacuum diffusion bonding at the Mg / Al interface. In summary, by strictly controlling the diffusion bonding process, the width of the Mg / Al diffusion layer can be effectively increased, while avoiding the formation of brittle intermetallic compounds at the Mg / Al interface. In addition, the vacuum diffusion bonding process not only effectively bonds the Mg / Al interface but also achieves medium-temperature diffusion annealing and stress removal at the Al / Ta interface, ensuring the overall forming of the composite plate. The entire process avoids the formation of a surface oxide layer, ensuring the interfacial bonding strength. At the same time, the process involved is relatively simple, including hot-dip galvanizing and vacuum diffusion bonding. Therefore, this method has high preparation efficiency for Mg-Al-Ta layered composite metal sheets, is suitable for the preparation of Mg-Al-Ta layered composite metal sheets, and the prepared Mg-Al-Ta layered composite metal sheets have high strength and strong dimensional and quality stability.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The Mg-Al-Ta layered composite metal sheet preparation method of the present invention uses hot-dip galvanizing + vacuum diffusion bonding to achieve effective Al / Ta bonding, and then uses vacuum diffusion bonding to achieve effective bonding of Mg alloy sheet and aluminum-plated Ta sheet, which can significantly improve the quality of sheet and improve aerospace carrying capacity.

[0024] 2. The method for preparing Mg-Al-Ta layered composite metal plates by hot-dip galvanizing and vacuum diffusion bonding of the present invention firstly uses hot-dip galvanizing technology to achieve the composite of pure Al and pure Ta plates. Compared with traditional solid-phase composite methods, hot-dip galvanizing technology has significant advantages such as short production cycle, fewer steps, low energy consumption, and avoidance of surface oxidation. Furthermore, due to the higher temperature, it can promote the mutual diffusion of Al and Ta atoms, forming a good interfacial metallurgical bonding effect. At the same time, the hot-dip aluminum coating layer can serve as an effective medium for subsequent bonding of Mg alloy plates and pure Ta plates, solving the problem of difficult metallurgical bonding between Ta and Mg.

[0025] 3. The method for preparing Mg-Al-Ta layered composite metal plates by hot-dip galvanizing and vacuum diffusion bonding of the present invention, in the second step, adopts the vacuum diffusion bonding method to realize the composite of aluminum-plated Ta plate and Mg alloy plate. Compared with the traditional rolling composite method, it effectively solves the mechanical bonding problem caused by the difficulty in coordinating the plasticity of dissimilar metals with large differences between Mg and Ta and the easy generation of residual stress, while realizing good metallurgical bonding of each interface.

[0026] 4. The method for preparing Mg-Al-Ta layered composite metal plates by hot-dip galvanizing and vacuum diffusion bonding of the present invention is particularly suitable for the processing and manufacturing of radiation-resistant lightweight layered composite materials for shielding structures of deep space probes. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are only some specific embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 Flowchart of the combined hot-dip galvanizing and vacuum diffusion bonding process for the preparation of Mg-Al-Ta composite metal plates of the present invention;

[0029] Figure 2 This is a schematic diagram of the apparatus used for hot-dip aluminizing of pure Ta plates according to the present invention;

[0030] In the figure, 1. Cleaned pure Ta plate, 2. Thermocouple, 3. Molten Al liquid, 4. Graphite crucible, 5. Induction furnace;

[0031] Figure 3 This is a schematic diagram of a single aluminum-plated Ta plate and two deformed Mg alloy plates of the present invention being alternately stacked and vacuum diffused together. Detailed Implementation

[0032] To further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0033] like Figure 1 As shown, the method for preparing Mg-Al-Ta layered composite metal sheets by hot-dip galvanizing and vacuum diffusion bonding of the present invention includes the following steps:

[0034] Step 1: Polish, clean, and vacuum dry the pure Ta plates and pure Al blocks to remove surface oil and oxide layers, and obtain cleaned pure Ta plates and pure Al blocks.

[0035] Step 2: Under a protective atmosphere, melt the cleaned pure Al block to obtain molten Al liquid;

[0036] Step 3: Immerse the cleaned pure Ta plate into molten Al liquid, remove and cool to complete the surface hot-dip aluminizing process, and obtain aluminized Ta plate;

[0037] Step 4: After surface polishing, cleaning, and vacuum drying of several aluminum-plated Ta plates and several deformed Mg alloy plates, they are stacked alternately to obtain a multi-layer structure plate.

[0038] Step 5: Vacuum diffusion bonding of the multi-layer structured plates to obtain Mg-Al-Ta layered composite metal plates.

[0039] In the above technical solution, the deformed Mg alloy sheet, pure Ta sheet, and pure Al block can all be commercially available. The pure Ta sheet undergoes stress-relief annealing heat treatment. The purity of the pure Ta sheet is preferably ≥99.99%, the purity of the pure Al block is preferably ≥99.6%, and the deformed Mg alloy sheet is preferably AZ31 wrought magnesium alloy sheet or EW75 wrought magnesium alloy sheet, with a deformation amount of 20%-60%, preferably 20%-50%. The initial thickness of the deformed Mg alloy sheet and the pure Ta sheet is typically 1mm-2mm.

[0040] In the above technical solution, in step one, it is preferred to use an angle grinder and wire brush to polish the surface of pure Al blocks and pure Ta plates. However, it should be noted that other surface polishing processes known to those skilled in the art are also applicable to this invention. Cleaning involves ultrasonic cleaning in anhydrous ethanol for 5-10 minutes. There are no special limitations, and any method known to those skilled in the art can be used as long as it can remove surface oil and oxide layers. The temperature for vacuum drying is 50℃-100℃. There are no special limitations on the drying equipment, which is usually a vacuum drying oven.

[0041] In the above technical solution, in step two, the pure Al block is preferably melted in an induction furnace with an argon protective atmosphere, and the temperature is controlled within the range of 750℃-850℃. After melting, the surface slag is removed. However, it should be noted that there are no other specific requirements for the melting equipment, and other melting methods well known to those skilled in the art are also applicable to this invention.

[0042] In the above technical solution, in step three, the hot-dip aluminum plating process temperature is preferably controlled at 750℃-850℃, and the immersion time is controlled at 5min-30min, preferably 5min-20min, and more preferably 800℃ hot-dip aluminum plating for 15min-16min. The entire process is carried out under an argon protective atmosphere. It should be noted that other anti-oxidation protective atmospheres or measures known to those skilled in the art are also applicable to this invention.

[0043] In the above technical solution, step three, there are no special restrictions on the equipment used for hot-dip aluminizing of pure Ta plates, such as... Figure 2 As shown, the molten Al liquid 3 can be placed in a graphite crucible 4, and the graphite crucible 4 can be placed in an induction furnace 5. A thermocouple 2 with the molten Al liquid 3 inserted at the bottom is set in the graphite crucible 4. The cleaned pure Ta plate 1 is immersed in the molten Al liquid 3 by vertical suspension.

[0044] In the above technical solution, step four preferably involves using an angle grinder and wire brush to polish the surface of the deformed Mg alloy plate and the aluminized Ta plate. Cleaning is performed by ultrasonic cleaning in anhydrous ethanol for 5-10 minutes, and vacuum drying is carried out at a temperature of 50℃-100℃. However, it should be noted that other surface polishing processes well-known to those skilled in the art are also applicable to this invention; there are no special limitations on cleaning, as long as a method well-known to those skilled in the art is used, and it effectively removes the surface oxide layer and inclusions; there are no special limitations on the vacuum drying equipment, which is typically a vacuum drying oven.

[0045] In the above technical solution, the purpose of selecting deformed magnesium alloy plates in step four is to increase the diffusion channels at the Mg / Al interface and promote vacuum diffusion bonding at the Mg / Al interface.

[0046] In the above technical solution, step four does not have specific requirements regarding the number of stacked layers; multiple layers can be stacked according to the usage requirements of the Mg-Al-Ta layered composite metal sheet. Preferably, there are N aluminum-plated Ta sheets and N+1 deformed Mg alloy sheets, where N≥1. The top and bottom layers of the multi-layered structure are both deformed Mg alloy sheets. Figure 3 As shown, when N=1, the stacking order is modified Mg alloy plate, aluminized Ta plate, and modified Mg alloy plate.

[0047] In the above technical solution, the preferred vacuum diffusion bonding process conditions in step five are: vacuum level below 10 Pa, pressure 15 MPa-50 MPa, temperature (0.6-0.8) × 650℃ (the melting point of Mg), and time above 1 hour, preferably 1-2 hours. It should be noted that, depending on the equipment capacity, appropriately increasing the vacuum level is beneficial for diffusion bonding.

[0048] The terminology used in this invention generally has the meanings commonly understood by those skilled in the art, unless otherwise stated. To enable those skilled in the art to better understand the technical solutions of this invention, the invention will be further described in detail below with reference to embodiments.

[0049] In the following embodiments, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, apparatus, instruments, equipment, etc., used in the following embodiments are commercially available.

[0050] The present invention will be further illustrated below with reference to the embodiments.

[0051] Example 1

[0052] The method for preparing Mg-Al-Ta layered composite metal sheets by hot-dip galvanizing and vacuum diffusion bonding includes the following steps:

[0053] Step 1: Take a piece of pure Ta board (initial thickness 2mm, purity 99.99%, area 100×50mm) 2 The surface of the annealed Ta plate and several pure Al blocks (99.6% purity) was polished, cleaned, vacuum dried, and the surface oil and oxide layer were removed to obtain the cleaned pure Ta plate and pure Al blocks.

[0054] Step 2: Place the cleaned pure Al block in an induction furnace with an argon protective atmosphere for melting (temperature controlled within the range of 750℃-850℃), remove the slag from the surface of the molten aluminum, and obtain molten Al liquid.

[0055] Step 3: Place the cleaned pure Ta plate in molten Al liquid for 15 minutes using the vertical suspension method, remove and cool it to complete the surface hot-dip aluminizing process (the hot-dip aluminizing process temperature is controlled at 800℃, and the whole process is carried out under argon protective atmosphere) to obtain aluminized Ta plate (Al / Ta / Al).

[0056] Step 4: Place one aluminized Ta plate and two deformed Mg alloy plates (AZ31, 1.5mm thick, 100×50mm in area) 2After surface grinding, cleaning, and vacuum drying, the deformed Mg alloy plate, aluminized Ta plate, and deformed Mg alloy plate were stacked in sequence to obtain a sandwich-shaped sample (Mg(AZ31)-Al / Ta / Al-Mg(AZ31)).

[0057] Step 5: Place the sandwich-shaped sample into a vacuum diffusion apparatus for vacuum diffusion bonding (vacuum degree below 10 Pa, pressure 25 MPa, temperature 400℃, time 1.5 h) to obtain a Mg-Al-Ta layered composite metal plate with high interfacial bonding strength.

[0058] Example 2

[0059] The method for preparing Mg-Al-Ta layered composite metal sheets by hot-dip galvanizing and vacuum diffusion bonding includes the following steps:

[0060] Step 1: Place two pure Ta plates (initial thickness 2mm, purity 99.99%, area 100×50mm) into a single plate. 2 The surface of the annealed Ta plate and several pure Al blocks (99.6% purity) was polished, cleaned, vacuum dried, and the surface oil and oxide layer were removed to obtain the cleaned pure Ta plate and pure Al blocks.

[0061] Step 2: Place the cleaned pure Al block in an induction furnace with an argon protective atmosphere for melting (temperature controlled within the range of 750℃-850℃), remove the slag from the surface of the molten aluminum, and obtain molten Al liquid.

[0062] Step 3: Place the cleaned pure Ta plate in molten Al liquid for 16 minutes using the vertical suspension method, remove and cool it to complete the surface hot-dip aluminizing process (the hot-dip aluminizing process temperature is controlled at 800℃, and the whole process is carried out under argon protective atmosphere) to obtain aluminized Ta plate (Al / Ta / Al).

[0063] Step 4: Take the two aluminum-plated Ta plates and one Mg alloy plate (EW75, 2mm thick, 100×50mm) obtained in Step 3. 2 After surface grinding, cleaning, and vacuum drying, the samples were prepared by alternating stacking of aluminum-plated Ta plates and deformed Mg alloy plates, with a deformation of 20%; to obtain sandwich-shaped samples (Ta / Al-Mg(EW75)-Al / Ta).

[0064] Step 5: Place the sandwich-shaped sample into a vacuum diffusion apparatus for vacuum diffusion bonding (vacuum degree below 10 Pa, pressure 25 MPa, temperature 400℃, time 1.5 h) to obtain a Mg-Al-Ta layered composite metal plate with high interfacial bonding strength.

[0065] Comparative Example 1

[0066] The preparation method of the Mg-Al-Ta layered composite metal sheet in this comparative example is the same as that in Example 1, except that the Mg alloy sheet is an annealed sheet that has not undergone deformation treatment.

[0067] Comparative Example 2

[0068] The preparation method of the Mg-Al-Ta layered composite metal sheet in this comparative example is the same as that in Example 1, except that a Mg alloy sheet with a deformation amount of 10% is selected.

[0069] Comparative Example 3

[0070] The preparation method of the Mg-Al-Ta layered composite metal sheet in this comparative example is the same as that in Example 1, except that the hot-dip aluminizing temperature of the pure Ta sheet is 700℃.

[0071] Comparative Example 4

[0072] The preparation method of the Mg-Al-Ta layered composite metal sheet in this comparative example is the same as that in Example 1, except that the hot-dip aluminizing temperature of the pure Ta sheet is 900℃.

[0073] The Mg-Ta layered composite metal plates prepared in Examples 1-2 and Comparative Examples 1-4 were tested, and the results are as follows.

[0074] The prepared Mg-Al-Ta layered composite metal sheet was subjected to surface quality and basal yield strength tests (test standard (GB / T 31541-2015)) and field emission electron microscopy (SEM) observation. It was found that the Mg-Al-Ta layered composite metal sheet prepared in Example 1 had good surface quality and good interlayer bonding. The interfacial yield strength of the Mg-Al-Ta layered composite metal sheet was 150 MPa, the Al-Ta interfacial diffusion width was 15 μm, and the Mg-Al interfacial diffusion width was 25 μm, indicating good interfacial bonding.

[0075] The prepared Mg-Al-Ta layered composite metal plates were subjected to surface quality and basal yield strength tests and field emission electron microscopy (SEM) observation. It was found that the Mg-Al-Ta layered composite metal plates prepared in Example 2 had good surface quality and good interlayer bonding. The interfacial yield strength of the Mg-Ta layered composite metal plates was 165 MPa, the Al-Ta interfacial diffusion width was 15 μm, and the Mg-Al interfacial diffusion width was 25 μm, indicating good interfacial bonding.

[0076] The Mg-Al-Ta layered composite metal sheet prepared in Comparative Example 1 has good surface quality. However, there are obvious pore defects at the Mg / Al interface of the sheet. The interfacial yield strength of the Mg-Ta layered composite metal sheet is 50 MPa, the diffusion width of the Al-Ta interface is 14.2 μm, and the diffusion width of the Mg-Al interface is 8 μm. This indicates that the use of modified magnesium alloy sheet can effectively improve the interfacial bonding ability.

[0077] The Mg-Al-Ta layered composite metal sheet prepared in Comparative Example 2 has good surface quality. However, there are some obvious pore defects at the Mg / Al interface of the sheet weld. The interfacial yield strength of the Mg-Ta layered composite metal sheet is 80 MPa, the Al-Ta interface diffusion width is 14.5 μm, and the Mg-Al interface diffusion width is 13 μm. This indicates that although using a magnesium alloy sheet with small deformation can improve the width of the interfacial diffusion layer to a certain extent, the interfacial diffusion is insufficient and there are pore defects, which is not conducive to improving the interfacial bonding ability.

[0078] The Mg-Al-Ta layered composite metal sheet prepared in Comparative Example 3 has good surface quality and good weldability. The interfacial yield strength of the Mg-Ta layered composite metal sheet is 45 MPa, the Al-Ta interfacial diffusion width is 5 μm, and the Mg-Al interfacial diffusion width is 20 μm. This indicates that selecting a suitable hot-dip galvanizing temperature can effectively increase the Al-Ta interfacial diffusion layer width, which is beneficial to improving the interfacial bonding ability. This shows that the hot-dip galvanizing temperature is a key factor in the successful preparation of the Mg-Al-Ta layered composite metal sheet in this invention.

[0079] The Mg-Al-Ta layered composite metal sheet prepared in Comparative Example 4 has good surface quality and good weldability. The Al-Ta interface diffusion width is 16 μm, but a lot of Al-Ta intermetallic compounds are formed at the interface, and the Mg-Al interface diffusion width is 20 μm. The interfacial yield strength of the Mg-Ta layered composite metal sheet is 35 MPa, exhibiting brittle fracture characteristics. This indicates that the hot-dip galvanizing temperature is the key factor for the successful preparation of the Mg-Al-Ta layered composite metal sheet in this invention.

[0080] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that various variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing Mg-Al-Ta layered composite metal sheets by hot-dip galvanizing and vacuum diffusion bonding, characterized in that, Includes the following steps: Step 1: Polish, clean, and vacuum dry the pure Ta plates and pure Al blocks to remove surface oil and oxide layers, and obtain cleaned pure Ta plates and pure Al blocks. Step 2: Under a protective atmosphere, melt the cleaned pure Al block to obtain molten Al liquid; Step 3: Immerse the cleaned pure Ta plate into molten Al liquid, remove and cool to complete the surface hot-dip aluminizing process, and obtain aluminized Ta plate; Step 4: After surface polishing, cleaning, and vacuum drying of several aluminum-plated Ta plates and several deformed Mg alloy plates, they are stacked alternately to obtain a multi-layer structure plate. Step 5: Vacuum diffusion bonding of the multi-layered structured plates to obtain Mg-Al-Ta layered composite metal plates; In step three, the hot-dip aluminizing process is carried out under a protective atmosphere, with the temperature of the molten Al liquid at 750℃-850℃ and the immersion time at 5min-30min. In step four, the deformed Mg alloy sheet is either AZ31 deformed magnesium alloy sheet or EW75 deformed magnesium alloy sheet, with a deformation amount of 20%-60%. In step five, the vacuum diffusion bonding process conditions are: vacuum degree below 10Pa, pressure 15MPa-50MPa, temperature (0.6-0.8)×650℃, and time above 1h.

2. The method for preparing a Mg-Al-Ta layered composite metal sheet by hot-dip galvanizing and vacuum diffusion bonding according to claim 1, characterized in that, In step one, The purity of pure Ta sheets is ≥99.99%, and the purity of pure Al blocks is ≥99.6%. The surfaces of pure Al blocks and pure Ta plates were polished using an angle grinder and a wire brush. The cleaning process involves ultrasonic cleaning in anhydrous ethanol for 5-10 minutes. The temperature for vacuum drying is 50℃-100℃.

3. The method for preparing a Mg-Al-Ta layered composite metal sheet by hot-dip galvanizing and vacuum diffusion bonding according to claim 1, characterized in that, In step two, The cleaned pure Al block was placed in an induction furnace filled with nitrogen for melting; The melting temperature of the cleaned pure Al block is controlled at 750℃-850℃; After melting, remove the surface scum from the molten Al liquid.

4. The method for preparing a Mg-Al-Ta layered composite metal sheet by hot-dip galvanizing and vacuum diffusion bonding according to claim 1, characterized in that, In step three, the cleaned pure Ta plate is immersed in molten Al liquid using a vertical suspension method.

5. The method for preparing a Mg-Al-Ta layered composite metal sheet by hot-dip galvanizing and vacuum diffusion bonding according to claim 1, characterized in that, In step four, The surfaces of aluminized Ta plates and deformed Mg alloy plates were polished using an angle grinder and a wire brush. The cleaning process involves ultrasonic cleaning in anhydrous ethanol for 5-10 minutes. The temperature for vacuum drying is 50℃-100℃.

6. The method for preparing a Mg-Al-Ta layered composite metal sheet by hot-dip galvanizing and vacuum diffusion bonding according to claim 1, characterized in that, In step four, there are N aluminum-plated Ta plates and N+1 deformed Mg alloy plates, where N ≥ 1. The top and bottom layers of the multi-layer structure plate are both deformed Mg alloy plates.

7. The method for preparing a Mg-Al-Ta layered composite metal sheet by hot-dip galvanizing and vacuum diffusion bonding according to claim 6, characterized in that, In step four, N=1, and the deformed Mg alloy plate, the aluminized Ta plate, and the deformed Mg alloy plate are stacked in sequence.

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