A method for preparing Mg-Ta layered composite metal plate by hot isostatic pressing diffusion bonding

Abstract

The application relates to a Mg-Ta layered composite metal plate hot isostatic pressing diffusion connection preparation method and belongs to the technical field of hot isostatic pressing. The technical problems of low production efficiency of the Mg-Ta layered composite metal plate preparation process in the prior art and poor interface bonding capacity of the Ta and dissimilar metal composite plate prepared by the hot isostatic pressing diffusion connection are solved. The preparation method is characterized in that the surfaces of a plurality of pure Ta plates are roughened and Al films are plated, then a plurality of dual-phase Mg-Li alloy plates and the plurality of pure Ta plates are alternately stacked in sequence, fixed in a bag, vacuumized, and hot isostatic pressed to obtain the Mg-Ta layered composite metal plate. The preparation method is high in efficiency, suitable for the preparation of large-area composite metal plates, high in strength of the prepared composite metal plate, and strong in size and quality stability, and is especially suitable for the processing and manufacturing of the radiation-resistant lightweight layered composite material for a deep space probe shielding structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hot isostatic pressing, and particularly relates to a hot isostatic pressing diffusion connection preparation method of Mg-Ta layered composite metal plate. BACKGROUND

[0002] To successfully explore Jupiter, two major technical difficulties are faced. One is the strong surface magnetic field of Jupiter and the high-density high-energy particle radiation problem in the orbit of Jupiter, and the other is the energy problem caused by the long distance of Jupiter. This puts forward double requirements for the anti-high-energy particle radiation capacity and light weight of the instruments and equipment of the probe. The upgrading and substantial weight reduction of light weight based on the existing structure design, materials and process technology is one of the important development directions of deep space exploration technology research (Optimization Design of Radiation Vault in Jupiter Orbiting Mission [J], J.Z. Wang, J.N. Ma, J.W. Qiu, D. Tian, A.W. Zhu, Q.X. Zhang, A.S. Zhou. IEEE Transactions on Nuclear Science, (66) 2019, 2179-2187.). Among them, the composite of heavy anti-radiation materials Ta, Nb and light structure metal material Mg is expected to alleviate the two technical problems of radiation and energy faced by the Jupiter probe. The analysis and calculation research on the anti-radiation material system of the Jupiter probe structure show that the Mg-Ta layered composite plate can effectively reduce the weight by about 45.1% under the premise of having the same anti-radiation effect as heavy metal materials, which has great potential in the development of deep space exploration technology. However, due to the metallurgical incompatibility of Mg and Ta, the melting points (the melting point of Ta is 2996℃, the melting point of Mg is 650℃), the crystal lattice types (Ta is BCC, Mg is HCP), the linear expansion coefficients and other physical and chemical properties and metallurgical properties of the two metals have great differences, so Mg-Ta connection is difficult, and there are few reports on the preparation process of Mg-Ta layered composite plate at home and abroad.

[0003] A Chinese patent with publication number CN113733685A reports a lightweight high-strength Mg-Al-Ta composite metal plate and its rolling forming method. Although it can realize the processing and preparation of Mg-Ta laminated composite plate, the process involves different temperature holding treatment of Mg plate and pure Ta plate respectively, and then the plates are stacked and fixed. The temperature change of the stacked plates before rolling deformation is difficult to effectively control, and the production efficiency is not high. A Chinese patent with publication number CN113352708A reports a lightweight high-strength Mg-Ta composite metal plate and its room temperature rolling forming method. Although this preparation method avoids the problems of plate oxidation and energy consumption that may be brought in by medium-high temperature rolling, in order to effectively reduce the residual stress between different metal plates and ensure the smooth progress of rolling deformation, low-temperature recovery annealing and high-temperature diffusion annealing need to be introduced between rolling passes, and multiple passes of rolling deformation are required, which is not efficient. A Chinese patent with publication number CN112742870A reports a preparation method of a shielding type magnesium-tantalum multilayer composite plate. Although it can realize the processing and preparation of Mg-Ta laminated composite plate, the process involves the use of vacuum medium-high temperature rolling to avoid the oxidation problem of the plate, which has high requirements for the rolling equipment and rolling environment, and the production efficiency is not high.

[0004] Most of the preparation methods used in the above patents are multi-pass medium-high temperature rolling processing and annealing heat treatment. Currently, there are few reports on the preparation of Mg-Ta laminated composite plate by hot isostatic pressing diffusion connection. Hot isostatic pressing technology has the characteristics of high production efficiency, high process stability, and can be used to obtain large-area high-strength solid-phase connection compared to rolling process. Existing literature shows that hot isostatic pressing technology can be used for large-area high-strength solid-phase connection of Ta and Cu, Ta and Al, and other dissimilar metals (High-purity metal tantalum and copper alloy solid-phase connection structure and performance research[D], Qian Hongbing, Harbin Institute of Technology). A Chinese patent with publication number CN101733544A reports a diffusion welding method for obtaining tantalum and copper, aluminum, titanium dissimilar metals by hot isostatic pressing.

[0005] However, the solid-phase connection of Ta and dissimilar metals shows that Ta and dissimilar metals are difficult to composite. The main reason is that Ta is extremely easy to form a dense oxide film and has significant self-repairing ability.

[0006] In addition, in the above-mentioned Ta and dissimilar metal composite technology, there is no method to improve the interface bonding ability of Ta and dissimilar metals from the aspects of surface roughness and surface quality. SUMMARY

[0007] One of the purposes of the present application is to solve the technical problem of low production efficiency of the Mg-Ta laminated composite metal plate preparation process in the prior art.

[0008] The second object of the present application is to solve the technical problem of poor interface bonding capacity in the prior art of preparing Ta and dissimilar metal composite plates by hot isostatic pressing diffusion bonding.

[0009] The technical scheme adopted by the present application to achieve the above-mentioned objects is as follows.

[0010] The present application provides a method for preparing Mg-Ta laminated composite metal plates by hot isostatic pressing diffusion bonding, comprising the following steps:

[0011] Step one, surface grinding, cleaning and vacuum drying of a plurality of dual-phase Mg-Li alloy plates and a plurality of pure Ta plates;

[0012] Step two, surface roughening, pickling, cleaning and vacuum drying of the cleaned plurality of pure Ta plates obtained in step one;

[0013] Step three, Al film plating on the surface of the plurality of pure Ta plates vacuum dried in step two;

[0014] Step four, cleaning and vacuum drying of the plurality of dual-phase Mg-Li alloy plates obtained in step one and the plurality of Al film plated pure Ta plates obtained in step three, then stacking them alternately, fixing them in a package, vacuumizing, and obtaining a pressing piece;

[0015] Step five, hot isostatic pressing of the pressing piece, removing the package, and obtaining Mg-Ta laminated composite metal plates.

[0016] Preferably, in step one, an angle grinder is used to grind the surface of the Mg-Li alloy plates and the pure Ta plates.

[0017] Preferably, in step one, the cleaning is chemical cleaning.

[0018] Preferably, in step one, the vacuum drying temperature is 100-150℃.

[0019] Preferably, in step two, the surface roughening of the pure Ta plates is machining threads or bosses on the surface of the pure Ta plates. More preferably, the process used for surface roughening of the pure Ta plates in step two is turning.

[0020] Preferably, in step two, the pickling is pickling with a Ta pickling solution for 20-40s.

[0021] Preferably, in step two, the cleaning is first water washing with deionized water, and then ultrasonic cleaning with IPA.

[0022] Preferably, in step two, the vacuum drying temperature is 100-150℃.

[0023] Preferably, in step three, the Al film is plated by magnetron sputtering, the magnetron sputtering temperature is 18-28℃, the magnetron sputtering power is 250-350W, the chamber pressure is 3.5-4.0×10Torr, the substrate rotation speed is 5-8r / min, and the sputtering rate is 30-40nm / min.

[0024] Preferably, before step three, the pure Al target for magnetron sputtering to plate the Al film is cleaned to remove surface oxides.

[0025] Preferably, in step four, the cleaning is chemical cleaning.

[0026] Preferably, in step four, the vacuum drying temperature is 100-150℃.

[0027] Preferably, in step four, the upper surface is a two-phase Mg-Li alloy plate and the lower surface is a pure Ta plate after the plates are alternately stacked.

[0028] Preferably, in step five, the hot isostatic pressing process is performed under nitrogen protection, the pressure is 100-120MPa, the temperature is (0.6-0.8)×650℃ of the Mg melting point, and the time is 3-5h or more.

[0029] The principle of the present application is that the Mg-Ta layered composite metal plate hot isostatic pressing diffusion connection preparation method, Mg-Li alloy plate, surface roughening and Al film plated pure Ta plate are stacked and fixed in the set order in turn, the composite of Mg-Li alloy plate and pure Ta plate is realized through vacuum hot isostatic pressing at (0.6-0.8) Tm (Mg) temperature, and the vacuum hot isostatic pressing avoids the problem that Mg and Ta are difficult to be cooperated with large plastic deformation encountered in the rolling process. In this process, the surface of the pure Ta plate is roughened, and the surface burrs are forcedly extruded into the Mg-Li alloy plate by using pressure in the vacuum hot isostatic pressing process, so that the heterogeneous metal atoms on both sides of the connection interface are diffused and reacted to realize the good solid phase connection effect between the Mg-Li alloy plate and the pure Ta plate. The surface is plated with Al film by using magnetron sputtering, which avoids the surface oxidation of the pure Ta plate on the one hand, and serves as an intermediate layer to "stick" the Mg-Li alloy plate and the pure Ta plate on the other hand, thereby improving the diffusion connection of the two mutually insoluble systems. The pure Ta plate and the Mg-Li alloy plate which have been surface roughened and plated with Al film are subjected to vacuum hot isostatic pressing, the vacuum hot isostatic pressing ensures that the pure Ta plate and the Mg-Li alloy plate are not deformed macroscopically, avoids the plastic instability and the generation of residual stress between the deformed plates in the rolling process, and realizes effective metallurgical bonding of the plates in the vacuum hot isostatic pressing holding process after mechanical bonding by surface roughening. The whole process is carried out in a vacuum condition, so that the surface oxidation layer is avoided, and the surface bonding strength is ensured. At the same time, the process is relatively simple, including magnetron sputtering and hot isostatic pressing, so that the preparation efficiency of the Mg-Ta layered composite metal plate is high under the method, the method is suitable for the preparation of the composite metal plate, and the prepared Mg-Ta layered composite metal plate has high strength, and the size and quality stability are strong.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] 1. The Mg-Ta layered composite metal plate hot isostatic pressing diffusion connection preparation method of the present application uses a lightweight Mg-Li alloy plate with a dual-phase instead of a traditional AZ series Mg alloy plate, and the Mg-Li alloy plate and the surface roughened and Al film plated pure Ta plate are stacked and hot isostatic pressed at medium temperature, which can significantly reduce the plate quality and improve the space transportation capacity; at the same time, the Li phase in the Mg-Li alloy plate and the Ta in the pure Ta plate have the same BCC crystal structure, which is beneficial to the atomic diffusion of the Mg-Li alloy plate and the pure Ta plate, and improves the interface bonding strength.

[0032] 2. The Mg-Ta layered composite metal plate prepared by hot isostatic pressing diffusion connection method of the application, which adopts hot isostatic pressing technology to perform solid-phase diffusion connection on Mg and Ta, has the advantages of short production cycle, less process and low energy consumption compared with the Mg-Ta layered composite metal plate prepared by traditional rolling + multi-pass intermediate annealing and other multi-pass complex processes, and the size and quality stability of the Mg-Ta layered composite metal plate prepared by hot isostatic pressing is high due to the fewer and more controllable process parameters in the hot isostatic pressing process.

[0033] 3. The Mg-Ta layered composite metal plate prepared by hot isostatic pressing diffusion connection method of the application, which adopts surface roughening on the pure Ta plate, effectively solves the mechanical bonding problem caused by the plasticity difficulty of the Mg and Ta dissimilar metals and the easy generation of residual stress.

[0034] 4. The Mg-Ta layered composite metal plate prepared by hot isostatic pressing diffusion connection method of the application, which adopts the process method of magnetron sputtering to perform low-temperature Al film plating on the pure Ta plate, avoids the surface oxidation problem of each metal layer when a composite intermediate Al layer is used in the process of high-temperature hot pressing or rolling. Moreover, the magnetron sputtering Al film plating has low cost, is not limited by the types and shapes of substrates, has high deposition rate and low deposition temperature, so the Al film has less impurities and high quality. The Al film plating on the Ta surface effectively solves the surface oxidation problem of the pure Ta plate in the process of hot isostatic pressing solid-phase connection and the metallurgical bonding difficulty with Mg.

[0035] 5. The Mg-Ta layered composite metal plate prepared by hot isostatic pressing diffusion connection method of the application is particularly suitable for the processing and manufacturing of the radiation-resistant lightweight layered composite material for shielding structures of deep space probes. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can also obtain different drawings according to these drawings without creative labor.

[0037] Figure 1 The preparation process flow chart of the hot isostatic pressing Mg-Ta layered composite metal plate of the application.

[0038] Figure 2 The structure schematic diagram of the hot isostatic pressing Mg-Ta layered composite metal plate of the application.

[0039] In the figure, 1 is a Mg-Li alloy plate, 2 is a pure Ta plate, 2-1 is surface roughening, and 2-2 is an Al film.

[0040] Figure 3An interface scanning electron micrograph of the Mg-Ta layered composite metal plate of Example 1 of the present application.

[0041] Figure 4 An interface scanning electron micrograph of the Mg-Ta layered composite metal plate of Example 2 of the present application. DETAILED DESCRIPTION

[0042] In order to further understand the present application, the preferred embodiments of the present application are described below, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present application, and are not limitations on the claims of the present application.

[0043] The hot isostatic pressing diffusion bonding preparation method of the Mg-Ta layered composite metal plate of the present application comprises the following steps:

[0044] Step one, surface grinding and cleaning of the several dual-phase Mg-Li alloy plates 1 and the several pure Ta plates 2 to remove surface oxide layers and inclusions, vacuum drying;

[0045] Step two, surface texturing 2-1, acid pickling, cleaning, and vacuum drying of the several pure Ta plates 2 obtained after cleaning in step one;

[0046] Step three, surface Al film plating 2-2 of the several pure Ta plates 2 after vacuum drying in step two;

[0047] Step four, cleaning of the several dual-phase Mg-Li alloy plates 1 obtained after cleaning in step one and the several Al film plated 2-2 pure Ta plates 2 obtained in step three to remove surface oxide layers and inclusions, vacuum drying, then stacking alternately, fixing in a package, welding, vacuumizing to obtain a piece to be pressed;

[0048] Step five, hot isostatic pressing of the piece to be pressed, mechanical engagement and metallurgical bonding of the Mg-Li alloy plates 1, the pure Ta plates 2, and the Al film plated 2-2, mechanical processing to remove the package, to obtain a Mg-Ta layered composite metal plate.

[0049] In the above technical solution, the Mg-Li alloy plates 1 and the pure Ta plates 2 can be obtained commercially, and both are subjected to stress relief annealing heat treatment. Among them, the Mg-Li alloy plates 1 are dual-phase structures, i.e. α+β phases, the Li phase in the Mg-Li alloy plates and the Ta in the pure Ta plates have the same BCC crystal structure, and the Mg-Li alloy plates 1 preferably use LA86M. The initial thickness of the Mg-Li alloy plates 1 and the pure Ta plates 2 is usually 2-3 mm. The number of several is not particularly limited, and can be more than 1, which is determined according to actual needs.

[0050] In the above technical solution, in step one, the surface of the Mg-Li alloy plate 1 and the pure Ta plate 2 is preferably polished by an angle grinder. However, it should be noted that other surface polishing processes known to those skilled in the art are also applicable to the present application.

[0051] In the above technical solution, in step one, the cleaning is chemical cleaning, which is not particularly limited and can be performed in a manner known to those skilled in the art, as long as it can remove the surface oxide layer and inclusions. Typically, a mixed acid of H2SO4:HF:HNO3=3:2:1 is used for surface treatment.

[0052] In the above technical solution, in step one, the temperature for vacuum drying is 100-150°C, and the drying equipment is not particularly limited, and is typically a vacuum drying oven.

[0053] In the above technical solution, in step two, the surface texturing 2-1 of the pure Ta plate 2 is preferably machining threads or bosses on the surface of the pure Ta plate 2, and the size of the threads or bosses is determined according to actual needs. For example, the thread spacing is 0.4-0.5 mm, the thread depth is 0.1-0.2 mm, and the thread angle is 97-100°; the boss height is 0.4-0.5 mm, the boss depth is 0.1-0.3 mm, and the boss angle is 90°. Typically, the process used for surface texturing 2-1 of the pure Ta plate 2 is turning. However, it should be noted that other machining methods known to those skilled in the art are also applicable to the present application.

[0054] In the above technical solution, in step two, the acid pickling is Ta acid pickling for 20-40 seconds, preferably 30 seconds. The Ta acid pickling is not particularly limited, as long as it can completely expose the fresh metal surface.

[0055] In the above technical solution, in step two, the cleaning is first water washing with deionized water, and then ultrasonic cleaning with IPA. However, it should be noted that other cleaning known to those skilled in the art is also applicable to the present application, as long as it can remove the acid used for pickling.

[0056] In the above technical solution, in step two, the temperature for vacuum drying is 100-150°C, and the drying equipment is not particularly limited, and is typically a vacuum drying oven.

[0057] The technical scheme, in step three, the process for plating the Al film 2-2 is magnetron sputtering, preferably direct current magnetron sputtering, and the pure Ta plate 2 has an Al film 2-2 that is small, uniform, dense, has almost no white agglomerates, holes and other defects on the surface, and has good adhesion. The process conditions for magnetron sputtering are preferably as follows: the magnetron sputtering temperature is 18-28℃, the magnetron sputtering power is 250-350W, the chamber pressure is 3.5-4.0x10 Torr, the substrate rotation speed is 5-8r / min, and the sputtering rate is 30-40nm / min; more preferably, the magnetron sputtering power is 300W, the chamber pressure is 3.7x10 Torr, the substrate rotation speed is 6r / min, and the sputtering rate is 36nm / min. Preferably, before step three, the pure Al target material used for plating the Al film 2-2 is subjected to magnetron sputtering to remove surface oxides. The Al film 2-2 avoids the formation of a self-repairing oxide film on the pure Ta plate 2 and improves the interfacial bonding capacity of the Mg-Li alloy plate 1 and the pure Ta plate 2.

[0058] The technical scheme, in step four, the cleaning is chemical cleaning, which is not particularly limited and can be performed in any manner known to those skilled in the art as long as it can remove the surface oxide layer and inclusions. Typically, it is chemical pickling.

[0059] The technical scheme, in step four, the temperature for vacuum drying is 100-150℃, and the drying equipment is not particularly limited and is typically a vacuum drying oven.

[0060] The technical scheme, in step four, the uppermost layer and the lowermost layer after being stacked alternately are not particularly limited and are typically a dual-phase Mg-Li alloy plate 1 on the upper surface and a pure Ta plate 2 on the lower surface. However, it should be noted that the number of Mg-Li alloy plates 1 and pure Ta plates 2 is not particularly limited and can be equal or unequal, and the thickness of the Mg-Ta layered composite metal plate can be set according to actual needs. Typically, the thickness of each of the Mg-Li alloy plate 1 and the pure Ta plate 2 is 2mm, but it is not limited thereto. Moreover, the upper and lower surfaces of the Mg-Ta layered composite metal plate are not particularly limited and can be both dual-phase Mg-Li alloy plates 1, both pure Ta plates 2, or one dual-phase Mg-Li alloy plate 1 and the other a pure Ta plate 2.

[0061] The technical scheme, in step five, the process conditions for hot isostatic pressing are a pressure of 100-120MPa, a temperature of (0.6-0.8)x650℃ of the Mg melting point, and a time of 3-5h or more. Preferably, the pressure is 100MPa, the temperature is 0.6-0.8 of the Mg melting point, and the time is 5h or more. The gas is preferably nitrogen.

[0062] The technical scheme, in step five, the sleeve is preferably a stainless steel sleeve.

[0063] The terms used in the present application generally have the meanings commonly understood by those of ordinary skill in the art, unless otherwise defined. In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the examples.

[0064] In the following examples, various processes and methods not described in detail are conventional methods known in the art. The materials, reagents, devices, instruments, equipment, etc. used in the following examples, unless otherwise specified, can be obtained commercially.

[0065] The present application will be further described below with reference to the examples.

[0066] Example 1

[0067] The Mg-Ta layered composite metal plate hot isostatic pressing diffusion connection preparation method has the following steps:

[0068] Step one, three pieces of Mg-Li alloy plate 1 (LA103M, initial thickness 2-3mm, area 1000mm 2 , conforms to GB / T5153-2016, annealed state) and three pieces of pure Ta plate 2 (initial thickness 2-3mm, purity 99.95%, area 1000mm 2 , annealed state) are polished for 3-5min using an angle grinder to remove surface contamination and oxide layer, cleaned, and vacuum dried.

[0069] Step two, the surface of the pure Ta plate 2 treated in step one is turned to form threads with a thread spacing of 0.45mm, a thread depth of 0.2mm, and a thread angle of 97°, immersed in a Ta pickling solution for chemical cleaning for 30s to remove surface oxides and inclusions, and vacuum dried.

[0070] Step three, a pure Al target (purity greater than 99.5%, area 1000mm 2 , conforms to GB / T 3880-2006, annealed state) is pre-sputtered to remove surface oxides using a direct current magnetron sputtering device, and then an Al film 2-2 is plated on the surface of the pure Ta plate 2 at low temperature (20℃) using a direct current magnetron sputtering device, with a magnetron sputtering power of 300W, a chamber pressure of 3.7x10 Torr, a substrate rotation speed of 6r / min, and a sputtering rate of 36nm / min, so that the surface of the pure Ta plate 2 is covered with a uniform and dense Al film 2-2.

[0071] Step four, the Mg-Li alloy plate 1 and the pure Ta plate 2 with the Al plated film 2-2 obtained in step one are again subjected to chemical cleaning to remove surface oxides and inclusions, and then the Mg-Li alloy plate 1 and the pure Ta plate 2 with the Al plated film 2-2 are alternately stacked (Mg-Ta-Mg-Ta-Mg-Ta) as shown in Figure 2 indicated, and fixed in a stainless steel sheath container. After welding, the stainless steel sheath is vacuumized.

[0072] Step five, the stainless steel sheath is placed into a hot isostatic pressing device, the hot isostatic pressing gas is nitrogen, the pressure is 100 MPa, the hot isostatic pressing temperature is 350℃, and the holding time is 5h. After that, the threads of the pure Ta plate 2 are completely extruded into the Mg-Li alloy plate 1, the Mg-Ta mechanical combination is good, and the atomic diffusion of Mg, Al and Ta layers is realized under the action of temperature and pressure. Among them, the β phase of the Al plated film 2-2 and the Mg-Li alloy plate 1 provides an effective diffusion channel for Mg and Ta, and promotes the diffusion connection of the Mg-Li alloy plate 1 and the pure Ta plate 2 which are two immiscible metals.

[0073] Step six, the stainless steel sheath is removed by mechanical processing to obtain a Mg-Ta layered composite metal plate with no residual stress and high interface bonding strength.

[0074] Example 2

[0075] The Mg-Ta layered composite metal plate is prepared by hot isostatic pressing diffusion connection, and the steps are as follows:

[0076] Step one, two Mg-Li alloy plates 1 (LA86M, initial thickness 3mm, area 1000mm 2 , in accordance with GB / T5153-L2016, annealed state) and two pure Ta plates 2 (initial thickness 2mm, purity 99.95%, area 1000mm 2 , annealed state) are polished for 3-5min by an angle grinder to remove surface contamination and oxide layer, cleaned and vacuum dried.

[0077] Step two, the pure Ta plate 2 after step one is processed by surface turning to form a boss, the boss height is 0.45mm, the boss depth is 0.2mm, the boss angle is 90°, the surface is immersed in a Ta pickling solution for chemical cleaning for 30s to remove surface oxides and inclusions, and then vacuum dried.

[0078] Step three, a direct current magnetron sputtering device is used to sputter Al on the pure Ta plate 2 to form an Al plated film 2-2, the purity of the pure Al target material is more than 99.5%, the area is 1000mm 2After pre-sputtering to remove surface oxides, the pure Ta plate 2 is coated with an Al film 2-2 at low temperature (20℃) using a direct current magnetron sputtering device, with a magnetron sputtering power of 320 W, a chamber pressure of 3.7 x 10 Torr, and a substrate rotation speed of 6 r / min, and the sputtering rate is 36 nm / min, so that the Ta surface is covered with a uniform and dense Al film 2-2.

[0079] Step four, the Mg-Li alloy plate 1 obtained in step one and the pure Ta plate 2 coated with the Al film 2-2 are again chemically cleaned to remove surface oxides and inclusions, and then the Mg-Li alloy plate 1 and the pure Ta plate 2 coated with the Al film 2-2 are alternately stacked (Mg-Ta-Mg-Ta) in sequence, fixed in a stainless steel sheath container, and after welding, the stainless steel sheath is vacuumized.

[0080] Step five, the stainless steel sheath is placed into a hot isostatic pressing device, the hot isostatic pressing gas is nitrogen, the pressure is 150 MPa, the hot isostatic pressing temperature is 400℃, and after holding for 8 h, the pure Ta plate 2 is completely screwed into the Mg-Li alloy plate 1, the Mg-Ta mechanical combination is good, and the atomic diffusion of Mg, Al and Ta layers is realized under the action of temperature and pressure, wherein the β phase of the Al film 2-2 and the Mg-Li alloy plate 1 provides an effective diffusion channel for Mg and Ta, and promotes the diffusion connection of the Mg-Li alloy plate 1 and the pure Ta plate 2 which are two immiscible metals.

[0081] Step six, the stainless steel sheath is removed by mechanical processing to obtain a Mg-Ta layered composite metal plate with no residual stress and high interface bonding strength.

[0082] Comparative Example 1

[0083] The preparation method of the Mg-Ta layered composite metal plate of the present comparative example is the same as that of Example 1, and the only difference is that the pure Ta plate 2 is not subjected to surface roughening 2-1.

[0084] Comparative Example 2

[0085] The preparation method of the Mg-Ta layered composite metal plate of the present comparative example is the same as that of Example 1, and the only difference is that the pure Ta plate 2 is not subjected to Al film 2-2 treatment, and the Al target is directly used as an intermediate layer to participate in stacking, and the stacking order is Mg-Al-Ta-Mg-Al-Ta-Mg-Al-Ta.

[0086] Comparative Example 3

[0087] The preparation method of the Mg-Ta layered composite metal plate of the present comparative example is the same as that of Example 1, and the only difference is that the pure Ta plate 2 is not subjected to Al film 2-2.

[0088] Comparative Example 4

[0089] The preparation method of the Mg-Ta layered composite metal plate in this comparative example is the same as that in Example 1, except that the Mg-Li alloy plate 1 is an HCP single-phase Mg-3Li alloy plate.

[0090] 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.

[0091] The prepared Mg-Ta layered composite metal plate was subjected to surface quality and basal yield strength tests and field emission electron microscopy (SEM) observations (e.g.) Figure 3 As shown in the figure, the Mg-Ta layered composite metal plate prepared in Example 1 has good surface quality, no obvious cracks at the edges, an interfacial yield strength of 130 MPa, an interfacial diffusion width of 14 μm, and good interfacial bonding.

[0092] The prepared Mg-Ta layered composite metal plate was subjected to surface quality and basal yield strength tests and field emission electron microscopy (SEM) observations (e.g.) Figure 4 As shown in the figure, the Mg-Ta layered composite metal plate prepared in Example 2 had good surface quality, no obvious cracks at the edges, an interfacial yield strength of 150 MPa, and an interfacial diffusion width of 13.5 μm, indicating good interfacial bonding.

[0093] In Comparative Example 1, the Mg-Ta layered composite metal sheet prepared cracked during the tensile testing process. The crack was located in the center, indicating that Mg and Ta failed to form an effective bond in the middle. This suggests that the surface roughening 2-1 of the pure Ta sheet 2 is a key factor in the successful preparation of the Mg-Ta layered composite metal sheet in this invention.

[0094] The Mg-Ta layered composite metal sheet prepared in Comparative Example 2 has good surface quality, but there are obvious pore defects at the weld interface. The interfacial yield strength of the Mg-Ta layered composite metal sheet is 80 MPa, and the interfacial diffusion width is 5.2 μm, indicating that the Al film 2-2 can effectively improve the bonding ability of Mg-Ta.

[0095] The Mg-Ta layered composite metal sheet prepared in Comparative Example 3 had no obvious pores or unwelded defects. The interfacial yield strength of the Mg-Ta layered composite metal sheet was 22 MPa and the interfacial diffusion width was 1.2 μm, indicating that the Al film 2-2 was the key factor for the successful preparation of the Mg-Ta layered composite metal sheet in this invention.

[0096] The Mg-Ta layered composite metal plate prepared in Comparative Example 4 has a surface quality that is acceptable, an interface yield strength of 81 MPa, an interface diffusion width of 8.1 μm, and the β phase of the surface BCC can effectively improve the bonding capacity of Mg-Ta.

[0097] Obviously, the above examples are only examples for clearly illustrating, but not limitation of the embodiments. For those skilled in the art, based on the above description, different forms of changes or variations can also be made. Here, it is not necessary and also impossible to enumerate all the examples. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding, characterized in that, Includes the following steps: Step 1: Polish, clean, and vacuum dry several duplex Mg-Li alloy plates and several pure Ta plates. Step 2: The cleaned pure Ta plates obtained in Step 1 are subjected to surface roughening, acid washing, cleaning, and vacuum drying. Step 3: Coat the surface of several pure Ta plates after vacuum drying in Step 2 with an Al film; Step 4: Clean the several duplex Mg-Li alloy plates obtained in Step 1 and the several pure Ta plates with Al film obtained in Step 3, vacuum dry them, stack them alternately, put them into a sleeve for fixation, and then vacuum to obtain the parts to be pressed. Step 5: Perform hot isostatic pressing on the part to be pressed, remove the cladding, and obtain Mg-Ta layered composite metal sheet.

2. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, In step one, An angle grinder was used to polish the surfaces of duplex Mg-Li alloy plates and pure Ta plates; The cleaning was chemical cleaning. The temperature for vacuum drying is 100-150℃.

3. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, In step two, Surface roughening of pure Ta plates involves machining threads or bosses on the surface of the pure Ta plates. Pickling involves using Ta pickling solution for 20-40 seconds; The cleaning process involves first rinsing with deionized water, followed by IPA ultrasonic cleaning. The temperature for vacuum drying is 100-150℃.

4. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 3, characterized in that, In step two, the surface roughening process for the pure Ta plate is turning.

5. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, In step three, the Al film is deposited using magnetron sputtering, with a magnetron sputtering temperature of 18-28℃, a magnetron sputtering power of 250-350W, a chamber pressure of (3.5-4.0)×10Torr, a substrate rotation speed of 5-8r / min, and a sputtering rate of 30-40nm / min.

6. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, Before step three, the surface oxides are removed by magnetron sputtering using a pure Al target for Al film deposition.

7. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, In step four, The cleaning was chemical cleaning. The temperature for vacuum drying is 100-150℃.

8. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, In step four, after being stacked alternately, the upper surface is a dual-phase Mg-Li alloy plate and the lower surface is a pure Ta plate.

9. The method for preparing Mg-Ta layered composite metal plates by hot isostatic pressing diffusion bonding according to claim 1, characterized in that, In step five, the hot isostatic pressing process conditions are: nitrogen protection, pressure 100-120 MPa, temperature (0.6-0.8) × 650℃ (the melting point of Mg), and time 3-5 hours or more.

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