Mg-Ta composite plate and preparation method thereof

Abstract

The application discloses a Mg-Ta composite plate and a preparation method thereof, and comprises the following steps: S1, selected pure tantalum plate and AZ series magnesium alloy plate with bimodal separation non-basal plane texture are stacked and fixed in the order of magnesium alloy plate, pure tantalum plate and magnesium alloy plate to obtain a rolling blank; S2, the rolling blank is subjected to rolling, first cryogenic treatment, roller power-on rolling and second cryogenic treatment in sequence, and the operation is repeated until a set rolling pass is reached, so that an intermediate product is obtained; and S3, the intermediate product is subjected to heat diffusion annealing treatment, so that the Mg-Ta composite plate is obtained. The Mg-Ta composite plate with good interface bonding can be prepared, and a foundation is laid for engineering application of the composite plate.

Description

Technical Field

[0001] This invention relates to the preparation of metal composite plates, specifically to a Mg-Ta composite plate and its preparation method. Background Technology

[0002] With the rapid development of my country's space program, its deep space exploration capabilities are constantly improving. In particular, Jupiter, as a potential habitable planet, has made the exploration of its orbit and surface one of the hot topics in future deep space exploration. However, Jupiter exploration presents greater challenges, mainly due to its powerful magnetic field and the high-density, high-energy particles in its orbit, creating a strong radiation environment that poses a significant challenge to the resistance of probe instruments to high-energy particle radiation. Foreign probes have adopted a method of installing sensitive components in shielded enclosures, typically made of high-atomic-number heavy metals. While using heavy metals can meet the radiation protection requirements of the probe's sensitive components, this method comes at a huge cost in terms of weight. Given my country's limited launch capacity in the short term, the structural mass of the payload that can be transported is relatively small. It is impossible to follow the design and manufacturing path of foreign Jupiter probes. Therefore, it is necessary to upgrade and significantly reduce the weight based on existing structural designs, materials, and manufacturing technologies.

[0003] Due to the low miscibility and significantly different crystal structures of Mg and Ta, traditional processes such as isothermal rolling, cumulative rolling, and high-temperature rolling are prone to causing interfacial bonding problems and premature cracking during the rolling process. Furthermore, for space probes, which must withstand extremely harsh mechanical environments including vibration and high loads, the interfacial bonding of the Mg / Ta layered composite plate must possess high bonding strength (the yield strength of the Mg / Ta interface must be >100 MPa) to meet the most severe load-bearing requirements of the structure under full mission cross-sections and to prevent interface cracking and damage under prolonged on-orbit vibration.

[0004] CN112742870A discloses a method for preparing a shielded magnesium-tantalum multilayer composite plate. Although it can realize the processing and preparation of Mg / Ta composite plates, its process involves high-temperature rolling in a vacuum to avoid oxidation of the plate, which places high demands on the rolling equipment and rolling environment, and the production efficiency is not high. At the same time, the magnesium alloy plates used in the above patents are mostly base-textured magnesium alloy plates prepared by traditional high-temperature hot rolling, and their plastic deformation capacity and rollability are significantly inferior to those of bimodal non-base-textured magnesium alloy plates. In addition, the study "Micromorphology and Mechanical Properties of Current-Assisted Cumulative Rolled Magnesium / Aluminum Layered Composite Plates [J]" (Peng Zhili, Yan Jiawei, Tang Jingzhao, Shen Yao, Mechanical Engineering Materials, 2019, 43(12): 1-6) shows that when current passes through a metal, it generates Joule heat, which puts the material in a thermally activated deformation state, thereby increasing the rolling bonding force at the interface of the composite plate. Summary of the Invention

[0005] The purpose of this invention is to provide a Mg-Ta composite plate and its preparation method, which can produce a Mg-Ta composite plate with good interfacial bonding, laying the foundation for the engineering application of this type of composite plate.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a Mg-Ta composite plate includes the following steps:

[0008] S1, the selected pure tantalum plate and the AZ-series magnesium alloy plate with bimodal separation non-basal surface texture are stacked and fixed in the order of magnesium alloy plate, pure tantalum plate and magnesium alloy plate to obtain the rolled billet.

[0009] S2, the rolled billet is rolled, first cryogenic treatment, rolled with the rolls energized, and then cryogenic treatment is performed in sequence. The operation is repeated until the set number of rolling passes is obtained to obtain the intermediate product.

[0010] S3, perform thermal diffusion annealing on the intermediate product to obtain Mg-Ta composite board.

[0011] Furthermore, the rolling process in S2 specifically involves rolling the billet at a roll speed of 600~1200 r / min and a roll temperature of 120~200℃, with a thinning rate of 45~60% per rolling pass.

[0012] Furthermore, the energized rolling in S2 is specifically as follows: during the rolling process, the upper and lower rolls are connected to the positive and negative terminals of a DC power supply, respectively, and the current passes perpendicularly through the rolling surface of the plate. The current parameters during the energized rolling are set as follows: constant current of 12000~30000A, voltage of 15~36V, and frequency of 180~300Hz.

[0013] Furthermore, the rotational speed of the rolls in S2 is set to 600~1200 r / min, and the reduction per pass is 10~30%.

[0014] Furthermore, the rolling process in S2 is specifically as follows: the first cryogenic treatment time and the second cryogenic treatment time are 120~360min each.

[0015] Furthermore, the thermal diffusion annealing treatment in S3 specifically involves: holding the intermediate product at a temperature of 400~470℃ for 0.5~5.0h, holding pressure of 0.05~0.1MPa, and then air-cooling to room temperature.

[0016] Furthermore, both the first and second cryogenic treatments were carried out in liquid nitrogen.

[0017] The Mg-Ta composite board prepared by the method described in this invention is a Mg-Ta composite board.

[0018] The beneficial effects of this invention are:

[0019] 1. This invention uses AZ-series magnesium alloy plates with bimodal separation non-base surface texture to replace traditional base surface textured plates. These plates are stacked and fixed with pure tantalum plates in a set order. Under medium and low temperature conditions of 120~200℃, single-pass large deformation (45%~60%) cumulative stacking rolling can be achieved, effectively avoiding the oxidation problem of plates rolled at medium and high temperatures, as well as the problem of easy cracking of conventional base surface textured magnesium alloy plates under low temperature rolling conditions.

[0020] 2. In this invention, large deformation is first achieved by medium-low temperature cumulative rolling to realize mechanical bonding between the interfaces of the plates. Then, small deformation is achieved by energizing the rolls, so that the material completes the rolling composite under the interaction of electroplasticity and local heating effect of current, promoting the transformation of mechanical bonding between the interfaces of the composite plates into metallurgical bonding.

[0021] 3. This invention performs a first cryogenic treatment after rolling and a second cryogenic treatment while the rolls are energized. This cryogenic treatment not only releases residual stress within the deformed sheet material but also effectively ensures the smooth progress of subsequent low-temperature cumulative rolling deformation with large deformation amounts. Compared to traditional low-temperature annealing, cryogenic treatment avoids potential sheet oxidation and energy consumption during heating and heat preservation.

[0022] 4. This invention involves immersing the board material in liquid nitrogen for cryogenic treatment. The liquid nitrogen used is a byproduct of the oxygen production industry, which is inexpensive, widely available, energy-saving, easy to store and transport, chemically stable, non-toxic and pollution-free, and extremely low in cost. Attached Figure Description

[0023] Figure 1This is a flowchart of the preparation method of the Mg-Ta composite plate described in this invention. Detailed Implementation

[0024] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0025] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0026] Example 1, see Figure 1 The method for preparing the Mg-Ta composite plate shown includes the following steps:

[0027] S1. Raw material preparation includes a pure tantalum plate with an initial thickness of 1.5 mm and a purity of 99.95%, and an AZ31 magnesium alloy plate with an initial thickness of 1.5 mm and a bimodal non-basal texture. Both the pure tantalum plate and the AZ31 magnesium alloy plate with a bimodal non-basal texture are in the annealed state to ensure that the original plates are in a fully annealed state, thus possessing good rolling deformation capability. The chemical composition of the AZ31 magnesium alloy plate should comply with the provisions of the national standard GB / T5153-2016. The selected pure tantalum plate and the AZ-series magnesium alloy plate with a bimodal non-basal texture are surface-ground for 3 min and 4 min respectively using an angle grinder, followed by subsequent pickling and acetone-alcohol cleaning to remove surface oxides and inclusions.

[0028] Selected pure tantalum plates and AZ-series magnesium alloy plates with bimodal separation non-basal surface texture are stacked and fixed in the order of magnesium alloy plates, pure tantalum plates, and magnesium alloy plates to obtain rolled billets.

[0029] S2 involves sequentially rolling the billet, performing a first cryogenic treatment, rolling with energized rolls, and a second cryogenic treatment. This process is repeated until the set number of rolling passes is reached. If the set number of rolling passes is two, an intermediate product is obtained. Specifically:

[0030] The rolled billet was subjected to medium-low temperature cumulative rolling at a temperature of 200℃, with a thinning rate of 55% per rolling pass. The rotation speed of the upper and lower rolls was set to 800 r / min, and the temperature of the upper and lower rolls was set to 160℃ to obtain a deformed sheet. The deformed sheet was then immersed in liquid nitrogen for a first cryogenic treatment for 200 min to obtain a first-treatment sheet.

[0031] The rolls are electrically powered and rolled. The upper and lower rolls are connected to the positive and negative terminals of a DC power supply, respectively. The roll voltage is set to 18V, the current is constant at 28000A, the roll speed is 800r / min, the frequency is 180Hz, and the reduction is 20% per pass. The current passes vertically through the rolling surface. Then, the rolls are immersed in liquid nitrogen for a second cryogenic treatment for 150 minutes to obtain a secondary treated sheet.

[0032] The secondary-treated sheet material is cut in half and surface-ground using an angle grinder for 3 minutes. This is followed by pickling and acetone / alcohol cleaning to remove surface oxides and inclusions. The halved materials are then stacked and fixed, and the rolling, first cryogenic treatment, rolling with energized rolls, and second cryogenic treatment are repeated until the set number of rolling passes are reached.

[0033] S3, perform thermal diffusion annealing on the intermediate product, and keep the intermediate product at 420°C for 4.5 hours with a pressure of 0.1 MPa, and air cool to room temperature to obtain Mg-Ta composite board.

[0034] The prepared Mg-Ta layered composite plate was subjected to surface quality and yield strength tests and field emission electron microscopy (SEM) observation. It was found that the surface quality of the layered composite plate prepared in Example 1 was good, with no obvious cracks at the edge of the plate. The interfacial yield strength of the Mg-Ta layered composite plate was ~110MPa, and the interfacial diffusion width of the Mg-Ta layered composite plate was 12.6μm, indicating good interfacial bonding.

[0035] Example 2: A method for preparing a Mg-Ta composite board, comprising the following steps:

[0036] S1. Raw material preparation, including a pure tantalum plate with an initial thickness of 2.0 mm and a purity of 99.95%, and an AZ31 magnesium alloy plate with a bimodal separation non-basal surface texture and an initial thickness of 2.0 mm. Both the pure tantalum plate and the AZ31 magnesium alloy plate with bimodal separation non-basal surface texture are in the annealed state. The chemical composition of the AZ31 magnesium alloy plate should comply with the provisions of the national standard GB / T5153-2016. The selected pure tantalum plate and the AZ-series magnesium alloy plate with bimodal separation non-basal surface texture are surface-ground for 4 min and 6 min respectively using an angle grinder, followed by subsequent pickling and acetone-alcohol cleaning to remove surface oxides and inclusions.

[0037] Selected pure tantalum plates and AZ-series magnesium alloy plates with bimodal separation non-basal surface texture are stacked and fixed in the order of magnesium alloy plates, pure tantalum plates, and magnesium alloy plates to obtain rolled billets.

[0038] S2 involves sequentially rolling the billet, performing a first cryogenic treatment, rolling with energized rolls, and a second cryogenic treatment. This process is repeated until the set number of rolling passes is reached. If the set number of rolling passes is three, an intermediate product is obtained. Specifically:

[0039] The rolled billet was subjected to medium-low temperature cumulative rolling at a temperature of 180℃, with a thinning rate of 45% per rolling pass. The rotation speed of the upper and lower rolls was set to 1200 r / min, and the temperature of the upper and lower rolls was set to 200℃ to obtain a deformed sheet. The deformed sheet was then immersed in liquid nitrogen for a first cryogenic treatment for 240 min to obtain a first-treatment sheet.

[0040] The rolls are subjected to an electric rolling process. The upper and lower rolls are connected to the positive and negative terminals of a DC power supply, respectively. The roll voltage is set to 25V, the current is constant at 29000A, the roll speed is 1200r / min, the frequency is 200Hz, and the reduction is 15% per pass. The current passes vertically through the rolling surface. Then, the rolls are immersed in liquid nitrogen for a second cryogenic treatment for 300min, resulting in a secondary treated sheet.

[0041] The secondary-treated sheet material is cut in half and surface-ground using an angle grinder for 3 minutes. This is followed by pickling and acetone / alcohol cleaning to remove surface oxides and inclusions. The halved materials are then stacked and fixed, and the rolling, first cryogenic treatment, rolling with energized rolls, and second cryogenic treatment are repeated until the set number of rolling passes are reached.

[0042] S3, the intermediate product is subjected to thermal diffusion annealing treatment, and the intermediate product is kept at a temperature of 470℃ for 3.0h, with a holding pressure of 0.08MPa, and then air-cooled to room temperature to obtain Mg-Ta composite board.

[0043] The prepared Mg-Ta layered composite plate was subjected to surface quality and yield strength tests and field emission electron microscopy (SEM) observation. It was found that the surface quality of the layered composite plate prepared in Example 2 was good, with no obvious cracks at the edge of the plate. The yield strength of the Mg / Ta layered composite plate interface was ~128MPa, and the diffusion width of the Mg-Ta layered composite plate interface was 11.9μm, indicating good interfacial bonding.

[0044] Comparative Example 1: The preparation method of the Mg-Ta composite plate in this comparative example is the same as that in Example 1, except that the AZ31 magnesium alloy plate in the raw material has a base surface texture feature.

[0045] Comparative Example 2: The preparation method of the Mg-Ta composite plate in this comparative example is the same as that in Example 1, except that the rolls were not electrically energized after the medium and low temperature rolling.

[0046] Comparative Example 3: The preparation method of the Mg-Ta composite plate in this comparative example is the same as that in Example 1, except that no cryogenic treatment was performed after rolling.

[0047] Comparative Example 4: The preparation method of the Mg-Ta layered composite plate in this comparative example is the same as that in Example 1, except that thermal diffusion annealing treatment was not performed after rolling.

[0048] In Comparative Example 1, after low-temperature cumulative rolling deformation in the first pass with large deformation, obvious edge cracks appeared at the edge of the magnesium plate, and subsequent deformation could not be carried out. This indicates that the use of bimodal separation non-basal textured AZ31 magnesium alloy plate is the key factor for the successful preparation of Mg-Ta composite plate in this invention.

[0049] The Mg-Ta composite plate prepared in Comparative Example 2 showed good surface quality, with obvious cracks at the plate edges. The interfacial yield strength of the Mg-Ta composite plate was ~38 MPa, and the interfacial diffusion width of the Mg-Ta layered composite plate was 4.8 μm, indicating that electric rolling was the key factor for the successful preparation of the Mg-Ta composite plate of this invention.

[0050] In Comparative Example 3, after the second large deformation low-temperature cumulative rolling deformation, obvious edge cracks appeared at the edge of the magnesium plate. The interfacial yield strength of the Mg-Ta composite plate was ~58MPa, and the interfacial diffusion width of the Mg-Ta layered composite plate was 9.3μm, indicating that cryogenic liquid nitrogen treatment is the key factor for the successful preparation of the Mg-Ta composite plate of this invention.

[0051] The surface quality of the layered composite plate prepared in Comparative Example 4 is acceptable, with a few cracks appearing at the edge of the plate. The interfacial yield strength of the Mg-Ta composite plate is ~45MPa, and the interfacial diffusion width of the Mg-Ta layered composite plate is 4.7μm, indicating that thermal diffusion annealing is the key factor for the successful preparation of the Mg-Ta composite plate of this invention.

[0052] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for preparing a Mg-Ta composite plate, characterized in that, Includes the following steps: S1, the selected pure tantalum plate and the AZ series magnesium alloy plate with bimodal separation non-basal surface texture are stacked and fixed in the order of magnesium alloy plate, pure tantalum plate and magnesium alloy plate to obtain the rolled billet. S2, the rolled billet is rolled, first cryogenic treatment, rolled with the rolls energized, and then cryogenic treatment is performed in sequence. The operation is repeated until the set number of rolling passes is obtained to obtain the intermediate product. The rolling process specifically involves rolling the billet at a roll speed of 600~1200 r / min and a roll temperature of 120~200℃, with a thinning rate of 45~60% per rolling pass. The specific process of energized rolling is as follows: During the rolling process, the upper and lower rolls are connected to the positive and negative terminals of a DC power supply, respectively. The current passes perpendicularly through the rolling surface of the sheet. The current parameters for energized rolling are set as follows: constant current of 12000~30000A, voltage of 15~36V, and frequency of 180~300Hz. The roll speed for energized rolling is set to 600~1200r / min, and the reduction per pass is 10~30%. Both the first and second cryogenic treatments were carried out in liquid nitrogen, with the first and second cryogenic treatment times ranging from 120 to 360 minutes each. S3, perform thermal diffusion annealing on the intermediate product. Specifically, perform thermal diffusion annealing on the intermediate product at a temperature of 400~470℃ for 0.5~5.0h, with a holding pressure of 0.05~0.1MPa, and air cool to room temperature to obtain Mg-Ta composite board.

2. A Mg-Ta composite board prepared by the method described in claim 1.

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