阅读说明：本技术 一种屏蔽型镁钽多层复合板的制备方法 (Preparation method of shielding type magnesium-tantalum multilayer composite board ) 是由 吕政� 马书旺 王健 杨剑 毛昌辉 梁秋实 戴赫 于 2020-12-14 设计创作，主要内容包括：本发明公开了一种屏蔽型镁钽多层复合板的制备方法,所述屏蔽型复合板包括钽或钽合金作为高Z金属相,镁或镁合金作为低Z金属相。本发明公开的镁/钽复合板制备方法包括以下步骤：(1)对钽板和镁板分别进行退火处理；(2)对退火后板材进行表面处理,去除表面的氧化层、杂质和油污；(3)将上一步骤得到的板材进行堆叠,随后放入包套中抽真空、封焊,制成板坯；(4)将组装好的板坯入炉加热保温,送入轧机进行轧制,空冷后去除包套,得到镁/钽双金属多层复合板。本发明通过轧制的方式将镁(镁合金)和钽(钽合金)两种材料进行整体复合,制备方法简单、成本低、易于工业化生产,可以替代传统的抗电子辐射屏蔽材料。(The invention discloses a preparation method of a shielding type magnesium-tantalum multilayer composite board, wherein the shielding type composite board comprises tantalum or tantalum alloy as a high-Z metal phase, and magnesium or magnesium alloy as a low-Z metal phase. The preparation method of the magnesium/tantalum composite board disclosed by the invention comprises the following steps of: (1) respectively annealing the tantalum plate and the magnesium plate; (2) carrying out surface treatment on the annealed plate to remove an oxide layer, impurities and oil stains on the surface; (3) stacking the plates obtained in the last step, and then putting the plates into a sheath for vacuumizing and seal welding to prepare a plate blank; (4) and putting the assembled plate blank into a furnace, heating and preserving heat, sending the plate blank into a rolling mill for rolling, and removing the sheath after air cooling to obtain the magnesium/tantalum bimetal multilayer composite plate. The invention integrally compounds the magnesium (magnesium alloy) and the tantalum (tantalum alloy) by rolling, has simple preparation method, low cost and easy industrial production, and can replace the traditional electron radiation resistant shielding material.)

1. The preparation method of the shielding type magnesium-tantalum multilayer composite board is characterized by comprising the following steps:

(1) annealing the initial plate: carrying out vacuum annealing treatment on the tantalum plate, cooling the tantalum plate to room temperature along with the furnace after annealing and heat preservation, and taking out the tantalum plate; annealing the magnesium plate, taking out the magnesium plate after annealing and heat preservation, and cooling the magnesium plate to room temperature;

(2) surface treatment: polishing the surfaces of the tantalum plate and the magnesium plate obtained in the step (1), and then removing oil stains;

(3) assembling a plate blank: stacking the tantalum plate and the magnesium plate obtained in the step (2), putting the stacked tantalum plate and magnesium plate into a sheath, vacuumizing, sealing and welding to prepare a plate blank;

(4) hot rolling and compounding: heating and insulating the plate blank obtained in the step (3); performing single-pass rolling compounding after the heat preservation is finished;

(5) and (4) air-cooling the plate blank obtained in the step (4) to room temperature, and removing the sheath to obtain the magnesium-tantalum multilayer composite plate.

2. The method according to claim 1, wherein the tantalum plate in step (1) is selected from pure tantalum or tantalum-tungsten alloy, the tantalum-tungsten alloy is one of Ta-2.5W, Ta-7.5W, Ta-10W, the total amount of unavoidable impurities in the pure tantalum or tantalum-tungsten alloy is less than 0.5%, and the thickness of the unavoidable impurities is 0.1-3.5 mm.

3. The manufacturing method according to claim 1, wherein the magnesium plate in the step (1) is selected from pure magnesium or magnesium alloy, and the magnesium alloy is one of Mg-aLi-bAl-cZn alloy, Mg-dAl-eZn alloy and Mg-fZn-gMn alloy; wherein in the Mg-aLi-bAl-cZn alloy, a is 4.0-15.0, b is 0.5-6.0, and c is 0.2-3.0; in the Mg-dAl-eZn alloy, d is 2.0-9.5, and e is 0.4-1.5; in the Mg-fZn-gMn alloy, f is 1.0-9.0, and g is 0.2-1.0; the total amount of inevitable impurities in the pure magnesium or the magnesium alloy is less than 0.3 percent, and the thickness of the inevitable impurities is 0.5-5.0 mm.

4. The method according to claim 1, wherein the tantalum plate in step (1) is vacuum annealed at 950 ℃ to 1550 ℃, held for 1 to 4 hours, and at a vacuum degree of 1.0 x 10 or less^-3pa; the annealing temperature of the magnesium plate is 250-460 ℃, and the heat preservation time is 0.5-3 h.

5. The method according to claim 1, wherein the step (3) is a step ofThe stacking form is a magnesium/tantalum double-layer stacking structure form or a magnesium/tantalum/magnesium three-layer stacking structure form; the sheath is made of pure Al, and a release agent is coated inside the sheath; the vacuum degree in the sheath is less than 1 x 10^-2pa and then sealing and welding.

6. The production method according to claim 1, wherein the step (4) is a hot rolling step of: the heating temperature of the plate blank is 250-500 ℃, and the heat preservation time is 10-60 min; the rolling adopts a double-roller mill or a four-roller mill, the rolling reduction of single-pass rolling is 25-70% of the thickness of the plate blank, and the strain rate is 3.5-9.5s^-1。

Technical Field

The invention relates to the technical field of non-ferrous metal materials, in particular to a preparation method of a shielding type magnesium-tantalum multilayer composite board.

Background

The high-energy electrons in the radiation environment of the complex space have extremely strong penetrating power, are easy to cause the radiation effect of the space electrons, cause ionization damage to devices in the spacecraft and have extremely great harm. In order to ensure the normal operation of the spacecraft in space, it is important to protect some radiation sensitive devices against electron radiation. The design of electron radiation protection is mainly based on three action processes of electrons and substances: (1) electron-electron inelastic scattering, low Z (atomic number) materials are more effective in inelastic scattering than high Z materials; (2) electron-atomic nucleus elastic scattering, and the effect of elastic scattering of the high-Z material is better than that of the low-Z material; (3) the high-Z material has a certain probability of releasing bremsstrahlung photons after being irradiated. In conclusion, the multilayer shielding design adopting the 'low Z/high Z' double-layer structure or the 'low Z/high Z/low Z' three-layer structure can effectively reduce the electron movement speed and block the electron transmission, and the shielding efficiency is superior to that of a single material.

However, due to the large gradient of property difference, the bonding form between the low Z material (Mg, Al) and the high Z material (Ta, W) has a large limitation in the past, and is mainly realized by the aid of a polymer material. For example, low-Z and high-Z bulk materials are combined using a high-analytical polymer with better radiation resistance as a binder (creep strength, wangshan. radiation shielding optimization of semiconductor devices under space electron irradiation [ J ]. university of shanghai bulletin (natural science edition), 2003(03): 259-); or the high-Z material powder and the high polymer material are uniformly mixed to prepare the coating, and then the coating is coated on the surface of the low-Z material (Chaoyuan cata, Rovinyun, Wangzhuangzhuang, Xuanjian, Wangshan. research on the radiation-resistant shielding method of the aircraft [ J ]. research on radiation and radiation technology, 2006(04): 205-. The low Z/high Z multilayer composite material prepared by using the high molecular material has obvious defects: 1) after long-term service, the high polymer material is easy to age, so that the stability of the whole structure is reduced; 2) the overall mechanical properties are less well behaved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of a shielding type magnesium-tantalum bimetal multilayer composite plate with integrated function/structure, so as to meet the requirement of space protection and shielding.

The invention is realized by the following technical scheme.

The preparation method of the shielding type magnesium-tantalum multilayer composite board is characterized by comprising the following steps:

(1) annealing the initial plate: putting the tantalum plate into a vacuum annealing furnace for vacuum annealing treatment, cooling the tantalum plate to room temperature along with the furnace after annealing and heat preservation, and taking out the tantalum plate; putting the magnesium plate into a heating furnace for annealing treatment, and directly taking out the magnesium plate from the heating furnace to cool to room temperature after annealing and heat preservation;

(2) surface treatment: polishing the surfaces of the tantalum plate and the magnesium plate obtained in the step (1), removing oxide skin and impurities on the surfaces, and then removing oil stains;

(3) assembling a plate blank: stacking the tantalum plate and the magnesium plate obtained in the step (2), putting the stacked tantalum plate and magnesium plate into a sheath, vacuumizing, sealing and welding to prepare a plate blank;

(4) hot rolling and compounding: putting the plate blank obtained in the step (3) into a heating furnace for heating and heat preservation; after the heat preservation is finished, taking out the plate blank from the furnace and immediately sending the plate blank into a rolling mill for single-pass rolling compounding;

(5) and (4) naturally cooling the plate blank obtained in the step (4) to room temperature in the air, removing the sheath, and finally obtaining the magnesium-tantalum multilayer composite plate.

Further, the tantalum plate in the step (1) is selected from pure tantalum or tantalum-tungsten alloy, the tantalum-tungsten alloy is one of Ta-2.5W (97.5% of Ta and 2.5% of W by mass), Ta-7.5W (92.5% of Ta and 7.5% of W by mass) and Ta-10W (90% of Ta and 10% of W by mass), the total amount of inevitable impurities in the pure tantalum or tantalum-tungsten alloy is less than 0.5%, and the thickness of the inevitable impurities is 0.1-3.5 mm.

Further, the magnesium plate in the step (1) is selected from pure magnesium or magnesium alloy, and the magnesium alloy is one of Mg-aLi-bAl-cZn alloy, Mg-dAl-eZn alloy and Mg-fZn-gMn alloy; wherein in the Mg-aLi-bAl-cZn alloy, a is 4.0-15.0, b is 0.5-6.0, and c is 0.2-3.0 (namely, the mass percentages of Li, Al and Zn are 4.0-15.0 percent, 0.5-6.0 percent and 0.2-3.0 percent); in the Mg-dAl-eZn alloy, d is 2.0-9.5, and e is 0.4-1.5 (namely, the mass percent of the alloy comprises 2.0-9.5% of Al and 0.4-1.5% of Zn); in the Mg-fZn-gMn alloy, f is 1.0-9.0, and g is 0.2-1.0 (namely, the mass percent of the alloy comprises 1.0-9.0% of Zn and 0.2-1.0% of Mn); the total amount of inevitable impurities in the pure magnesium or the magnesium alloy is less than 0.3 percent, and the thickness of the inevitable impurities is 0.5-5.0 mm.

Further, the vacuum annealing temperature of the tantalum plate in the step (1) is 950-1550 ℃, the heat preservation time is 1-4h, and the vacuum degree is less than or equal to 1.0 multiplied by 10^-3pa; the annealing temperature of the magnesium plate is 250-460 ℃, and the heat preservation time is 0.5-3 h.

Further, in the step (2), the polishing mode of the surface of the magnesium plate is fine sand paper polishing, the polishing mode of the tantalum plate is stainless steel wire brush polishing, and the oil removing mode is acetone cleaning and drying.

Further, the stacking form in the step (3) is a stacking structure form of a magnesium/tantalum double layer or a stacking structure form of a magnesium/tantalum/magnesium triple layer; the sheath is made of pure Al, and a boron nitride separant is coated inside the sheath; the vacuum degree in the sheath is less than 1 x 10^-2pa and then sealing and welding.

Further, hot rolling in the step (4): the heating temperature of the plate blank is 250-500 ℃, and the heat preservation time is 10-60 min; the rolling adopts a double-roller mill or a four-roller mill, the rolling reduction of single-pass rolling is 25-70% of the thickness of the plate blank, and the strain rate is 3.5-9.5s^-1。

The rolling composite method adopted by the invention can realize the preparation of the dissimilar metal composite board, the process flow is simple, and the large-scale production can be realized; the interface of the rolled composite plate is usually physical mechanical bonding or metallurgical bonding, the interface bonding is tight, and the overall strength can reach the base metal strength with lower strength. In the aspect of material selection, the Z value of magnesium is low, the electronic deceleration capacity is good, the density is lower than that of aluminum, the specific strength is high, and the thermoplastic processing can be carried out; the Z value of tantalum is high, electrons can be effectively prevented from permeating, and the tantalum is rich in ductility, extremely low in thermal expansion coefficient and good in corrosion resistance. The shielding type magnesium-tantalum bimetal composite plate is prepared by adopting a rolling composite method, and the requirement of space radiation-resistant reinforcement integration can be met.

The invention has the beneficial technical effects that:

(a) according to the invention, the two metals with great property difference of magnesium and tantalum are compounded together by a rolling method, so that the limitation of the conventional low Z/high Z material combination mode is broken through, and the composite plate has better mechanical performance.

(b) In the invention, the low Z material is selected from pure magnesium and various magnesium alloys, and the high Z material is selected from pure tantalum and various tantalum alloys; the plastic deformation process of different low Z/high Z composite boards has great difference, and the invention performs plastic deformation process exploration on the low Z/high Z composite boards to finally obtain the magnesium-tantalum bimetallic composite boards with various types and specifications.

(c) In the invention, the magnesium-tantalum composite plate is rolled and compounded by adopting a double-roller or four-roller rolling mill, and because the plastic deformation capacities of the two materials are obviously different, an obvious 'saw-toothed' interface physical combination can be generated in the deformation process, and the 'saw-toothed' interface combination form is favorable for the firm combination between the interfaces and the overall mechanical property of the composite plate.

The preparation method is based on the special requirement of space electron radiation resistance, the preparation of the magnesium/tantalum bimetal composite plate is realized in a rolling compounding mode, and the limitation of a combination mode between the conventional low-Z material and the conventional high-Z material is broken through; the preparation method is simple, high in efficiency and easy for industrial production; compared with the traditional space electronic radiation resistance, the bimetal composite board prepared by the invention realizes the function/structure integration of the space protection shielding material and can be applied in a more severe space environment.

Drawings

FIG. 1 is an SEM (scanning electron microscope) appearance of a rolling-normal section of a double-layer magnesium/tantalum rolling composite plate;

FIG. 2 is an SEM morphology of the roll-to-normal cross-section of a three-layer magnesium/tantalum/magnesium rolled composite plate;

figure 3 is the EDS line scan analysis of the magnesium-tantalum interface.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Example 1

Pure tantalum with the thickness of 2.5mm and Mg-5Zn-1Mn magnesium alloy with the thickness of 4.0mm are selected, and the total amount of inevitable impurities in the pure tantalum/magnesium alloy is less than 0.3 percent.

The preparation method of the shielding type magnesium-tantalum bimetal composite plate comprises the following steps:

(a) annealing the initial plate: annealing pure tantalum in a vacuum annealing furnace, wherein the annealing temperature is 1000 ℃, the heat preservation time is 1.5h, and the furnace is cooled to the room temperature; annealing the magnesium alloy in a common resistance furnace at the annealing temperature of 420 ℃ for 2.5h, taking out the magnesium alloy from the furnace after the heat preservation is finished, and air-cooling the magnesium alloy to room temperature;

(b) surface treatment: polishing the pure tantalum plate and the magnesium alloy plate obtained in the step (a) by using a stainless steel wire brush and fine abrasive paper respectively to remove oxide skins and impurities on the surfaces, then washing and removing oil on the surfaces of the two polished plates by using acetone, and finally drying the two plates;

(c) assembling a plate blank: stacking the tantalum plate and the magnesium alloy plate obtained in the step (b) to form a Mg-5Zn-1Mn/Ta double-layer structure, and then putting the stacked composite plate into a pure Al sheath coated with a boron nitride release agent inside; vacuumizing the sheath when the vacuum degree in the sheath is lower than 1 x 10^-2Carrying out seal welding on the degassing port after pa to finally prepare a plate blank;

(d) hot rolling and compounding: putting the plate blank obtained in the step (c) into a heating furnace for heating and heat preservation, wherein the heating temperature is 440 ℃, and the heat preservation time is 50 min; after the heat preservation is finished, taking the plate blank out of the furnace, immediately sending the plate blank into a two-roller mill for single-pass rolling compounding, wherein the reduction is 70 percent of the total thickness of the plate blank, and the strain rate is 8.5s^-1。

(e) And after the hot rolling is finished, naturally cooling the plate blank to room temperature in the air, removing the sheath and finally obtaining the Mg-5Zn-1Mn/Ta double-layer composite plate.

The result shows that the Mg-5Zn-1Mn/Ta double-layer composite board is prepared by the rolling preparation process, the interface combination of the composite board is good, and the SEM appearance of the rolling direction-normal section is shown in figure 1.

Example 2

Selecting a Ta-7.5W tantalum alloy plate with the thickness of 1.5mm and a Mg-6Al-1Zn magnesium alloy with the thickness of 2.0mm, wherein the total amount of inevitable impurities in the tantalum alloy is less than 0.5 percent, and the total amount of inevitable impurities in the magnesium alloy is less than 0.3 percent.

The preparation method of the shielding type magnesium-tantalum bimetal composite plate comprises the following steps:

(a) annealing the initial plate: annealing the tantalum alloy in a vacuum annealing furnace, wherein the annealing temperature is 1350 ℃, the heat preservation time is 1.0h, and the furnace is cooled to the room temperature; annealing the magnesium alloy in a common resistance furnace at the annealing temperature of 440 ℃ for 2.0h, taking out the magnesium alloy from the furnace after the heat preservation is finished, and air-cooling the magnesium alloy to room temperature;

(b) surface treatment: respectively polishing the tantalum alloy plate and the magnesium alloy plate obtained in the step (a) by using a stainless steel wire brush and fine abrasive paper to remove oxide skins and impurities on the surfaces, then washing and removing oil on the surfaces of the two polished plates by using acetone, and finally drying the two plates;

(c) assembling a plate blank: stacking the tantalum plate and the magnesium alloy plate obtained in the step (b) to form a Mg-6Al-1Zn/Ta-7.5W/Mg-6Al-1Zn three-layer structure, and then putting the stacked composite plate into a pure Al sheath coated with a boron nitride release agent inside; vacuumizing the sheath when the vacuum degree in the sheath is lower than 1 x 10^-2Carrying out seal welding on the degassing port after pa to finally prepare a plate blank;

(d) hot rolling and compounding: putting the plate blank obtained in the step (c) into a heating furnace for heating and heat preservation, wherein the heating temperature is 470 ℃, and the heat preservation time is 45 min; after the heat preservation is finished, taking the plate blank out of the furnace, immediately sending the plate blank into a double-roller mill for single-pass rolling compounding, wherein the reduction is 50 percent of the total thickness of the plate blank, and the strain rate is 6.0s^-1。

(e) And after the hot rolling is finished, naturally cooling the plate blank to room temperature in the air, removing the sheath, and finally obtaining the Mg-6Al-1Zn/Ta-7.5W/Mg-6Al-1Zn three-layer composite plate.

Results show that the Mg-6Al-1Zn/Ta-7.5W/Mg-6Al-1Zn three-layer composite board is prepared by the rolling process, the interface combination of the composite board is good, and the SEM appearance of the rolling direction-normal direction section and the EDS first scanning plane analysis results of the magnesium-tantalum interface are respectively shown in attached figures 2 and 3.

Example 3

Pure tantalum with the thickness of 0.3mm and Mg-10Li-3Al-3Zn magnesium alloy with the thickness of 1.0mm are selected, and the total amount of inevitable impurities in the pure tantalum/magnesium alloy is less than 0.3 percent.

The preparation method of the shielding type magnesium-tantalum composite board comprises the following steps:

(a) annealing the initial plate: annealing pure tantalum in a vacuum annealing furnace, wherein the annealing temperature is 1000 ℃, the heat preservation time is 1.0h, and the furnace is cooled to the room temperature; annealing the magnesium alloy in a common resistance furnace at the annealing temperature of 280 ℃ for 2.0h, and taking out the magnesium alloy from the furnace after the heat preservation is finished and air-cooling the magnesium alloy to room temperature;

(b) surface treatment: polishing the pure tantalum plate and the magnesium alloy plate obtained in the step (a) by using a stainless steel wire brush and fine abrasive paper respectively to remove oxide skins and impurities on the surfaces, then washing and removing oil on the surfaces of the two polished plates by using acetone, and finally drying the two plates;

(c) assembling a plate blank: stacking the tantalum plate and the magnesium alloy plate obtained in the step (b) to form a Mg-10Li-3Al-3Zn/Ta/Mg-10Li-3Al-3Zn three-layer structure, and then putting the stacked composite plate into a pure Al sheath coated with a boron nitride release agent inside; vacuumizing the sheath when the vacuum degree in the sheath is lower than 1 x 10^-2Carrying out seal welding on the degassing port after pa to finally prepare a plate blank;

(d) hot rolling and compounding: putting the plate blank obtained in the step (c) into a heating furnace for heating and heat preservation, wherein the heating temperature is 260 ℃, and the heat preservation time is 40 min; after the heat preservation is finished, taking the plate blank out of the furnace, immediately sending the plate blank into a four-roller mill for single-pass rolling compounding, wherein the reduction is 30 percent of the total thickness of the plate blank, and the strain rate is 4.5s^-1。

(e) And after the hot rolling is finished, naturally cooling the plate blank to room temperature in the air, removing the sheath, and finally obtaining the Mg-10Li-3Al-3Zn/Ta/Mg-10Li-3Al-3Zn three-layer composite plate.

Example 4

Selecting a Ta-2.5W tantalum alloy plate with the thickness of 3.5mm and a Mg-4Li-6Al-0.3Zn magnesium alloy with the thickness of 5.0mm, wherein the total amount of inevitable impurities in the tantalum alloy is less than 0.5 percent, and the total amount of inevitable impurities in the magnesium alloy is less than 0.3 percent.

The preparation method of the shielding type magnesium-tantalum composite board comprises the following steps:

(a) annealing the initial plate: annealing the tantalum alloy in a vacuum annealing furnace, wherein the annealing temperature is 1200 ℃, the heat preservation time is 3.0h, and the tantalum alloy is cooled to the room temperature along with the furnace; annealing the magnesium alloy in a common resistance furnace at the annealing temperature of 250 ℃ for 1.0h, and taking out the magnesium alloy from the furnace after the heat preservation is finished and air-cooling the magnesium alloy to room temperature;

(b) surface treatment: respectively polishing the tantalum alloy plate and the magnesium alloy plate obtained in the step (a) by using a stainless steel wire brush and fine abrasive paper to remove oxide skins and impurities on the surfaces, then washing and removing oil on the surfaces of the two polished plates by using acetone, and finally drying the two plates;

(c) assembling a plate blank: stacking the tantalum plate and the magnesium alloy plate obtained in the step (b) to form a Mg-4Li-6Al-0.3Zn/Ta-2.5W double-layer structure, and then putting the stacked composite plate into a pure Al sheath coated with a boron nitride release agent inside; vacuumizing the sheath when the vacuum degree in the sheath is lower than 1 x 10^-2Carrying out seal welding on the degassing port after pa to finally prepare a plate blank;

(d) hot rolling and compounding: putting the plate blank obtained in the step (c) into a heating furnace for heating and heat preservation, wherein the heating temperature is 260 ℃, and the heat preservation time is 50 min; after the heat preservation is finished, taking the plate blank out of the furnace, immediately sending the plate blank into a four-roller mill for single-pass rolling compounding, wherein the reduction is 25 percent of the total thickness of the plate blank, and the strain rate is 3.5s^-1。

(e) And after the hot rolling is finished, naturally cooling the plate blank to room temperature in the air, removing the sheath, and finally obtaining the Mg-4Li-6Al-0.3Zn/Ta-2.5W double-layer composite plate.

Example 5

Selecting a Ta-10W tantalum alloy plate with the thickness of 3mm and a Mg-9.5Al-0.4Zn magnesium alloy with the thickness of 5.0mm, wherein the total amount of inevitable impurities in the tantalum alloy is less than 0.5 percent, and the total amount of inevitable impurities in the magnesium alloy is less than 0.3 percent.

The preparation method of the shielding type magnesium-tantalum composite board comprises the following steps:

(a) annealing the initial plate: the tantalum alloy is annealed in a vacuum annealing furnace at 1450 ℃, the heat preservation time is 2.5h, and the vacuum degree is 1.0 multiplied by 10^-3pa, furnace cooling to room temperature; annealing the magnesium alloy in a common resistance furnace at the annealing temperature of 460 ℃ for 3.0h, taking out the magnesium alloy from the furnace after the heat preservation is finished, and air-cooling the magnesium alloy to room temperature;

(b) surface treatment: respectively polishing the tantalum alloy plate and the magnesium alloy plate obtained in the step (a) by using a stainless steel wire brush and fine abrasive paper to remove oxide skins and impurities on the surfaces, then washing and removing oil on the surfaces of the two polished plates by using acetone, and finally drying the two plates;

(c) assembling a plate blank: stacking the tantalum plate and the magnesium alloy plate obtained in the step (b) to form a Mg-9Al-0.4Zn/Ta-10W/Mg-9Al-0.4Zn three-layer structure, and then putting the stacked composite plate into a pure Al sheath coated with a boron nitride release agent inside; vacuumizing the sheath when the vacuum degree in the sheath is lower than 1 x 10^-2Carrying out seal welding on the degassing port after pa to finally prepare a plate blank;

(d) hot rolling and compounding: putting the plate blank obtained in the step (c) into a heating furnace for heating and heat preservation, wherein the heating temperature is 450 ℃, and the heat preservation time is 60 min; after the heat preservation is finished, taking the plate blank out of the furnace, immediately sending the plate blank into a double-roller mill for single-pass rolling compounding, wherein the reduction is 60 percent of the total thickness of the plate blank, and the strain rate is 8.5s^-1。

(e) And after the hot rolling is finished, naturally cooling the plate blank to room temperature in the air, removing the sheath, and finally obtaining the Mg-9Al-0.4Zn/Ta-10W/Mg-9Al-0.4Zn three-layer composite plate.

Example 6

Pure tantalum with the thickness of 2mm and Mg-9Zn-0.3Mn magnesium alloy with the thickness of 0.5mm are selected, and the total amount of inevitable impurities in the pure tantalum/magnesium alloy is less than 0.3 percent.

The preparation method of the shielding type magnesium-tantalum composite board comprises the following steps:

(a) annealing the initial plate: pure tantalum is annealed and annealed in a vacuum annealing furnaceThe fire temperature is 1000 ℃, the heat preservation time is 1.5h, and the vacuum degree is 0.9 multiplied by 10^-3pa, furnace cooling to room temperature; annealing the magnesium alloy in a common resistance furnace at the annealing temperature of 460 ℃ for 0.5h, taking out the magnesium alloy from the furnace after the heat preservation is finished, and air-cooling the magnesium alloy to room temperature;

(b) surface treatment: polishing the pure tantalum plate and the magnesium alloy plate obtained in the step (a) by using a stainless steel wire brush and fine abrasive paper respectively to remove oxide skins and impurities on the surfaces, then washing and removing oil on the surfaces of the two polished plates by using acetone, and finally drying the two plates;

(c) assembling a plate blank: stacking the tantalum plate and the magnesium alloy plate obtained in the step (b) to form a Mg-9Zn-0.3Mn/Ta two-layer structure, and then putting the stacked composite plate into a pure Al sheath coated with a boron nitride release agent; vacuumizing the sheath when the vacuum degree in the sheath is lower than 1 x 10^-2Carrying out seal welding on the degassing port after pa to finally prepare a plate blank;

(d) hot rolling and compounding: putting the plate blank obtained in the step (c) into a heating furnace for heating and heat preservation, wherein the heating temperature is 500 ℃, and the heat preservation time is 10 min; after the heat preservation is finished, taking the plate blank out of the furnace, immediately sending the plate blank into a double-roller mill for single-pass rolling compounding, wherein the reduction is 40 percent of the total thickness of the plate blank, and the strain rate is 5.5s^-1。

(e) And after the hot rolling is finished, naturally cooling the plate blank to room temperature in the air, removing the sheath and finally obtaining the Mg-9Zn-0.3Mn/Ta two-layer composite plate.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention. It should be noted that other equivalent modifications can be made by those skilled in the art in light of the teachings of the present invention, and all such modifications can be made as are within the scope of the present invention.