A method for preparing an aluminum / magnesium composite material with an added composite interlayer

Abstract

This invention relates to the preparation technology of aluminum-magnesium layered composite materials with added composite interlayers, belonging to the field of metallic materials. The composite material specifically comprises an aluminum alloy matrix layer, a composite interlayer, and a magnesium alloy matrix layer. The specific preparation method is as follows: selecting suitable aluminum alloys and magnesium alloy matrices; stacking the aluminum matrix / composite interlayer / magnesium matrix; and obtaining a lightweight, high-strength, and well-bonded aluminum / magnesium layered composite material through vacuum hot-pressing diffusion bonding. The aluminum matrix / composite interlayer / magnesium matrix composite material prepared by this invention combines the advantages of lightweight and high strength of aluminum and magnesium matrices. It innovatively selects Ni / Al, Ti / Al, Ti / Cu, etc., as composite interlayers, simultaneously achieving solid-phase diffusion and transient liquid-phase diffusion on both sides of the interlayer. The prepared composite material has advantages such as high metallurgical bonding strength, good interfacial bonding, and excellent comprehensive mechanical properties. The preparation process is clean, environmentally friendly, and easy to control, and can be used for large-scale production.

Description

Technical Field

[0001] This invention relates to the preparation technology of aluminum-magnesium layered composite materials with added composite intermediate layers, belonging to the field of metallic materials. Background Technology

[0002] As the lightest engineering metal material currently available, magnesium alloys are hailed as "green engineering materials of the 21st century." Due to their low density, high specific strength, good machinability, and high damping capacity, magnesium alloys are widely used in aerospace and automotive industries. However, magnesium alloys themselves have poor corrosion resistance, poor plastic deformation capacity, and are prone to brittle fracture. Therefore, in actual production, magnesium alloys are combined with aluminum alloys, which have better plasticity, corrosion resistance, and weldability, to form composite materials. This combines the excellent properties of both materials, further improving overall mechanical properties and broadening application areas.

[0003] Common methods for preparing aluminum-magnesium composites include brazing, diffusion bonding, rolling composite, bimetallic composite casting, and friction stir welding. Brazing uses a metal with a low melting point as the filler metal, utilizing the temperature difference between the filler metal and the base metal to completely melt the filler metal, allowing it to wet and spread onto the base metal surface for metallurgical bonding, thus achieving the welding effect. Diffusion bonding utilizes the free diffusion of atoms when different metals are in close contact under external influences, enabling surface atomic migration and solid-state welding. Explosive bonding utilizes the large amount of energy generated by an explosion to cause complex reactions such as high-speed collisions, friction, interlocking, and diffusion on the surfaces of the metals being welded, resulting in a strong bond between the metal surfaces. Unlike the previous composite methods, which are mainly solid-phase bonding, bimetallic casting composite first melts the coating metal and then pours it onto the surface-treated base metal; or the base metal is immersed in the coating metal liquid, and the energy released by the cooling of the liquid phase promotes atomic diffusion, forming a continuous diffusion zone, thus achieving composite between dissimilar metals. The rolling composite method involves generating a large amount of plastic deformation under rolling pressure, and after the surface layers are activated, they diffuse into each other and eventually form a metallurgical bond.

[0004] Currently, during the composite process, Al-Mg intermetallic compounds Al3Mg2 and Al are formed at the interface. 12 Mg 17 It is both brittle and hard, prone to brittle fracture, and has a large difference in thermal expansion coefficient with the matrix, making it susceptible to stress concentration and cracking, resulting in poor interfacial bonding strength. Current solutions involve adding an interlayer to hinder the interdiffusion between aluminum and magnesium, reducing the formation of brittle phases or altering their distribution. Simultaneously, the interlayer forms a solid solution or a better-matched new phase with the two matrices, improving bonding strength. For example, existing patent CN114769587A describes an aluminum-magnesium layered composite material with an added Ni interlayer.

[0005] The preparation method involves adding a nickel layer, and this technology yielded aluminum-magnesium layered composite materials with a shear strength of 82-84 MPa for the first time. To further enhance the room temperature shear strength of the aluminum-magnesium layered composite materials, the research group conducted further research based on CN114769587A, leading to this invention. Summary of the Invention

[0006] This invention provides a method for preparing aluminum-magnesium composite materials with an added composite interlayer. By adding an A / B structure interlayer, the direct diffusion between magnesium and aluminum is prevented from forming brittle intermetallic compounds. At the same time, a new phase with better matching degree is generated, which greatly improves the bonding performance of the aluminum-magnesium composite material interface and obtains an aluminum-magnesium composite material with good interfacial metallurgical bonding.

[0007] The main problems to be solved in this invention are:

[0008] (1) How to coordinate the relationship between the interfacial bonding strength and the sintering temperature and holding time. When the sintering temperature is high and the holding time is long, the aluminum-magnesium matrix and the intermediate layer undergo a strong diffusion reaction at the interface, producing a large amount of intermetallic compound aggregation, which makes the interfacial layer too thick and affects the bonding strength of the aluminum-magnesium composite material; when the sintering temperature is low and the holding time is short, the diffusion rate is slow, and the aluminum-magnesium matrix cannot form a strong metallurgical bond with the intermediate layer.

[0009] (2) How to improve the bonding strength between the matrix and the intermediate layer? The weakest point of aluminum-magnesium composite material is generally at the interface between the intermediate layer and the matrix. It is necessary to adjust the phase composition and distribution state at the interface to have a better matching relationship, such as coherent or semi-coherent relationship, so as to ensure that the metallurgical bonding of the interface layer is better.

[0010] To address the above issues and obtain aluminum-magnesium composite materials with good interfacial bonding, the following schemes are proposed based on extensive exploratory experiments, including the selection of aluminum and magnesium matrices, the selection of intermediate layers, and diffusion bonding of aluminum alloy matrix / intermediate layer / magnesium alloy matrix.

[0011] This invention discloses a method for preparing an aluminum / magnesium composite material with an added composite interlayer. First, an aluminum alloy matrix and a magnesium alloy matrix are selected. Then, an interlayer is selected, with an A / B structure. Before the reaction, one side of layer A contacts the aluminum alloy matrix, and the other side contacts layer B. The other side of layer B contacts the magnesium alloy matrix. At the reaction temperature, layer A maintains its integrity, preventing direct diffusion between the aluminum and magnesium alloy matrices and forming a good metallurgical bond with the aluminum alloy. At the reaction temperature, layer B forms a eutectic liquid phase wetting interface with the magnesium alloy, and under applied pressure, excess liquid phase is squeezed out, while a new phase is generated, forming a metallurgical bond with both layer A and the magnesium alloy.

[0012] In industrial applications, the grades of the base aluminum alloy and magnesium alloy can be selected according to requirements. The base aluminum alloy is selected from one of the following: 2A12 aluminum alloy, 6061 aluminum alloy, 7075 aluminum alloy, 5083 aluminum alloy, etc. The above aluminum alloys can meet the requirements for strength, corrosion resistance, and weldability.

[0013] The magnesium alloy is selected from one of the following: AZ31 magnesium alloy, AZ91 magnesium alloy, ZK61 magnesium alloy, AM60 magnesium alloy, WE43 magnesium alloy, etc. These magnesium alloys meet the requirements for strength, ductility, and damping. The matrix can be prepared by methods such as casting, deformation, 3D printing, or powder metallurgy, with the specific method chosen based on the alloy grade.

[0014] The selection criteria for the intermediate layer are as follows: The intermediate layer hinders diffusion between aluminum and magnesium while forming intermetallic compounds and solid solutions with the matrix, and the resulting new phase forms a good metallurgical bond with the matrix. Specifically, high-melting-point metals such as Ti, Ag, and Ni have less dissolution and diffusion, maintaining the integrity of the intermediate layer and effectively preventing the large-scale diffusion of aluminum and magnesium, as well as the formation of numerous hard and brittle aluminum-magnesium intermetallic compounds. Furthermore, they generate a new interface layer, enhancing the bonding strength of the interface. Metals such as Cu, Al, Sn, and Zn form numerous new phases with the matrix and further react in the high-melting-point intermediate layer, achieving good bonding on both sides. In addition, rare earth (RE) elements are highly metallic and readily combine with other metal elements to form rare earth precipitates, which have a refining and strengthening effect, and a second-phase precipitation strengthening effect, thereby strengthening the interface. Depending on the requirements, two or more of the above intermediate layers can be selected to form a composite intermediate layer. For example, Ni / Al, Ti / Al, and Ti / Cu can be used as composite intermediate layers, ensuring both the integrity of the interface layer and a good metallurgical bond with the matrix.

[0015] When Ni / Al, Ti / Al, Ti / Cu, etc. are selected as composite intermediate layers, they can prevent the direct diffusion between magnesium and aluminum to form brittle intermetallic compounds, while generating new phases with better matching degree, which greatly improves the bonding performance of the aluminum-magnesium composite interface and obtains aluminum-magnesium composite materials with good interfacial metallurgical bonding.

[0016] The diffusion bonding technology for preparing aluminum-magnesium composite materials with added composite interlayers according to the present invention comprises the following steps:

[0017] (1) The aluminum alloy and magnesium alloy substrates were prepared into layers, and the surfaces were cleaned with sandpaper and then ultrasonically cleaned with alcohol.

[0018] (2) Select intermediate layer A and intermediate layer B with dimensions matching the size of the substrate, clean the surface with sandpaper and then clean with alcohol and ultrasonic cleaning.

[0019] (3) Place the magnesium substrate / intermediate layer B / intermediate layer A / aluminum substrate stacked together, with the magnesium side at the top of the sample, and put it into the graphite mold;

[0020] (4) Place the graphite mold containing the sample into the sintering furnace, set the heating program, perform hot-press diffusion connection under vacuum conditions, and cool with the furnace to obtain an aluminum-magnesium composite material with an added composite intermediate layer. The sintering temperature of the hot-press diffusion connection is higher than the eutectic reaction temperature of the Mg matrix and the composite intermediate layer, and lower than the eutectic reaction temperature of the Al matrix and the intermediate layer.

[0021] or

[0022] The sintering temperature is higher than the eutectic reaction temperature of the Al matrix and the composite intermediate layer, but lower than the eutectic reaction temperature of the Mg matrix and the intermediate layer.

[0023] Preferably, the aluminum alloy substrate, magnesium alloy substrate, intermediate layer A, and intermediate layer B are surface-treated with 400-800 grit wet sandpaper, and then cleaned with alcohol in an ultrasonic cleaner for 5-10 minutes, 2-3 times. To further improve product quality, after alcohol cleaning, the products are allowed to air dry in a vacuum environment.

[0024] Preferably, the thickness of A is 20-50 micrometers and the thickness of B is 10-30 micrometers.

[0025] The intermediate layer A is selected from at least one of Ti, Cu, Ni, Al, Zn, Sn, and Ag.

[0026] Intermediate layer B is selected from at least one of Ti, Cu, Ni, Al, Zn, Sn, and Ag, but the material of intermediate layer B is different from that of intermediate layer A;

[0027] Preferably, the material of the intermediate layer A is selected from at least one of Ti, Ni, etc.

[0028] Preferably, the material of the intermediate layer B is selected from at least one of Al, Cu, and Ni.

[0029] Intermediate layer A / intermediate layer B can preferably be one of the following structures: Ni / Al, Ti / Al, Ti / Cu, Ti / Cu, Ti / Ni. That is, if intermediate layer A is Ni, then the matching intermediate layer B is Al or Cu; if intermediate layer A is Ti, then the matching intermediate layer B is Al, Cu, or Ni.

[0030] In practical applications, the thickness of the magnesium substrate layer can be greater than or equal to 0.1 mm, preferably greater than or equal to 0.2 mm, which of course includes a series of thickness options such as 2-15 mm and 20-10 mm.

[0031] In practical applications, the thickness of the aluminum substrate layer can be greater than or equal to 0.1 mm, preferably greater than or equal to 0.2 mm, which of course includes a series of thickness options such as 2-15 mm and 20-10 mm.

[0032] In laboratory exploration, preferably, in step (1), the aluminum-magnesium matrix is ​​cut into circular pieces with a diameter of 40 mm and a thickness of 2-10 mm, and the surface is treated with 400-mesh and 800-mesh wet sandpaper, and then cleaned with alcohol in an ultrasonic cleaner for 5-10 minutes, 2-3 times.

[0033] Preferably, the vacuum condition mentioned in step (4) refers to a gas pressure inside the sintering furnace of less than 0.1 Pa, more preferably a gas pressure inside the furnace of less than 0.01 Pa;

[0034] Preferably, the pressure of the low-pressure sintering in step (4) is 5-20 MPa, more preferably 8-15 MPa;

[0035] Preferably, the gradient heating process in step (4) is as follows: heating from room temperature to sintering temperature at a heating rate of 5-10℃ / min, holding at that temperature for 0.5-2 hours, and finally cooling with the furnace to obtain a powder metallurgy aluminum-magnesium composite material with an added composite intermediate layer.

[0036] The gradient heating sintering process described above can better control the heating rate and temperature deviation during the sintering process, allowing for full diffusion between the aluminum-magnesium matrix and the intermediate layer, resulting in a tight interface bond.

[0037] In actual industrial applications, the magnesium substrate / Al foil / Ni foil / aluminum substrate are stacked in the order of magnesium substrate / Al foil / Ni foil / aluminum substrate, with the magnesium side on top of the sample, and then placed into a graphite mold.

[0038] The graphite mold containing the sample was placed in a vacuum sintering furnace, and a vacuum of 2*10 was applied. -2 After Pa, heating begins, first increasing the temperature to 460℃ at 10℃ / min and holding for 10 minutes, then holding at 460℃ for 1 hour, while simultaneously pressurizing at 460℃ to a pressure of 10MPa. After the process is completed, pressurization is stopped and the material is cooled with the furnace to obtain an aluminum-magnesium composite material with an added Ni / Al composite interlayer.

[0039] In actual industrial applications, the magnesium substrate / Al foil / Ti foil / aluminum substrate are stacked in the order of magnesium substrate / Al foil / Ti foil / aluminum substrate, with the magnesium side on top of the sample, and then placed into a graphite mold.

[0040] The graphite mold containing the sample was placed in a vacuum sintering furnace, and a vacuum of 2*10 was applied. -2After Pa, heating begins, increasing the temperature to 550℃ at a rate of 10℃ / min and holding for 10 minutes. The temperature is then maintained at 550℃ for 1 hour, while simultaneously pressurizing at 550℃ to a pressure of 10MPa. After the process is completed, pressurization is stopped and the material is cooled with the furnace to obtain an aluminum-magnesium composite material with an added Ti / Al composite interlayer.

[0041] In practical industrial applications, the samples are stacked in the following order: magnesium substrate / Cu foil / Ti foil / aluminum substrate, with the magnesium side on top. The sample is then placed inside a graphite mold, and the mold containing the sample is placed in a vacuum sintering furnace, where a vacuum of 2*10⁻⁶ is applied. -2 After Pa, heating begins, increasing the temperature to 540℃ at 10℃ / min and holding for 10 minutes, then holding at 540℃ for 1 hour. Simultaneously, pressure is applied at 540℃ with a pressure of 10 MPa. After the process is completed, pressure is stopped and the furnace is cooled to obtain an aluminum-magnesium composite material with an added Ti / Cu composite interlayer.

[0042] This patent selects Ni / Al, Ti / Al, Ti / Cu, etc. as composite intermediate layers. The high melting point of Ti and Ni not only hinders the direct diffusion between aluminum and magnesium to form intermetallic compounds, but also changes the phase composition at the interface, generating a new phase at the interface, thus realizing the composite of aluminum and magnesium materials.

[0043] In this invention, the thickness of intermediate layer A should be set to ensure its integrity during the reaction process; the thickness of intermediate layer B should be set to ensure that it is completely consumed during the composite process through eutectic reactions, forming discontinuously distributed intermetallic compounds, precipitates, or solid solutions. Generally, the metal foil layer thickness is greater than 1 micrometer, and the electroplated metal layer thickness ranges from 0.1 micrometer to 50 micrometers.

[0044] The aluminum-magnesium composite material obtained by this invention has a shear strength of 80~130 MPa.

[0045] In industrial applications, the intermediate layer B is sintered at the temperature and time is controlled to allow it to completely react and become an intermetallic compound. However, at this time, the intermediate layer A must still be attached to the aluminum substrate in a continuous state and form a metallurgical bond with the aluminum substrate.

[0046] The principle of this invention:

[0047] This invention effectively prevents the formation of brittle intermetallic compounds through direct contact between the aluminum and magnesium matrices by adding a composite interlayer. While ensuring good metallurgical bonding between Ti or Ni and the Al side, metals such as Al and Cu are added to the Mg side, reacting with the Mg side to form a new phase with better bonding, greatly improving the bonding strength on the Mg side. After numerous experimental studies and improvements, Ni / Al, Ti / Al, and Ti / Cu were selected as composite interlayers, and aluminum-magnesium composite materials with added composite interlayers were successfully prepared under different sintering temperatures and pressures, significantly improving their shear strength.

[0048] Advantages of this invention:

[0049] First, this process is easy to operate, significantly reduces production costs, and has high economic benefits.

[0050] Second, the added composite intermediate layer is very thin, so it has little impact on the overall quality.

[0051] Third, the range of choices for the added composite intermediate layer is wide. This invention is applicable to the preparation of various alloy matrix / intermediate layer / alloy matrix composite materials. The composition of the alloy matrix and intermediate layer can be selected according to actual needs, the composition control is flexible, and the application fields are wide. Attached Figure Description

[0052] Appendix Figure 1 The interfacial microstructure of the aluminum-magnesium composite material with Ni / Al composite interlayer added in Example 1;

[0053] Appendix Figure 2 The interfacial microstructure of the aluminum-magnesium composite material with a Ti / Al composite interlayer added in Example 2;

[0054] Appendix Figure 3 The interfacial microstructure of the aluminum-magnesium composite material with a Ti / Cu composite interlayer added in Example 3;

[0055] Appendix Figure 4 The interfacial microstructure of the aluminum-magnesium composite material with a Ni / Cu composite interlayer added in Example 4;

[0056] Appendix Figure 5 The interfacial microstructure of the aluminum-magnesium composite material with a Ni / Al composite interlayer added to Comparative Example 1;

[0057] Appendix Figure 6 The interfacial microstructure of the aluminum-magnesium composite material with a Ni / Cu composite interlayer added to Comparative Example 5;

[0058] Appendix Figure 7 The interfacial microstructure of the aluminum-magnesium composite material with a Ni / Cu composite interlayer added to Comparative Example 6 Detailed Implementation

[0059] Example 1:

[0060] (1) The 2A12 aluminum alloy and AZ31 magnesium alloy prepared by powder metallurgy were surface treated with 400 mesh and 800 mesh water sandpaper respectively, and ultrasonically cleaned with alcohol 3 times, each time for 2 minutes. The substrate was a circular piece with a thickness of 4.5 mm and a diameter of 40 mm.

[0061] (2) Cut 30 μm thick pure Ni foil and 15 μm thick pure Al foil into circular pieces with a diameter of 40 mm, and clean them along with the substrate.

[0062] (3) Stack the magnesium substrate / Al foil / Ni foil / aluminum substrate in the order of magnesium substrate / Al foil / Ni foil / aluminum substrate, with the magnesium side on top of the sample, and place it into the graphite mold;

[0063] (4) Place the graphite mold containing the sample into a vacuum sintering furnace and evacuate it to a vacuum level of 2*10. -2 After Pa, heating begins, increasing the temperature to 460℃ at a rate of 10℃ / min and holding for 10 minutes. The temperature is then maintained at 460℃ for 1 hour, while simultaneously pressurizing at 460℃ to a pressure of 10MPa. After the process is completed, pressurization is stopped and the material is cooled with the furnace to obtain an aluminum-magnesium composite material with an added Ni / Al composite interlayer.

[0064] Example 1 shows that the aluminum-magnesium composite material with Ni / Al composite interlayer has a dense interface layer. After sintering and hot pressing, the Al-Mg intermetallic compounds are reduced and mainly exist in the form of precipitates. A large number of new phases Al3Ni2 are generated at the interface, which are well bonded to both the Ni interlayer and the Mg side. The resulting aluminum-magnesium composite material has a shear strength of 127.76 MPa, which is much higher than the 20-30 MPa of general aluminum-magnesium composite materials.

[0065] Example 2

[0066] Other conditions are the same as in Example 1, except that a Ti / Al composite intermediate layer is used, wherein the thickness of the pure Ti foil is 50 μm and the thickness of the Al foil is 15 μm. This results in step (3) being stacked in the order of magnesium substrate / Al foil / Ti foil / aluminum substrate, with the magnesium side on top of the sample, and placed into the graphite mold;

[0067] Steps (1) to (3) are the same as in Example 1, except that: the temperature is increased to 550℃ at 10℃ / min and held for 10 minutes, and then held at 550℃ for 1 hour. At the same time, the pressure is increased at 550℃ with a pressure of 10 MPa. After the process is completed, the pressure is stopped and the furnace is cooled to obtain an aluminum-magnesium composite material with an added Ti / Al composite intermediate layer.

[0068] The aluminum-magnesium composite material with added Ti / Al composite interlayer has an interfacial shear strength of 125.58 MPa.

[0069] Example 3

[0070] Other conditions are the same as in Example 1, except that a Ti / Cu composite intermediate layer is used, wherein the thickness of the pure Ti foil is 30 μm and the thickness of the Cu foil is 10 μm. This results in step (3) being stacked in the order of magnesium substrate / Cu foil / Ti foil / aluminum substrate, with the magnesium side on top of the sample, and placed into the graphite mold;

[0071] Steps (1) to (3) are the same as in Example 1, except that: the temperature is increased to 540℃ at 10℃ / min and held for 10 minutes, and then held at 540℃ for 1 hour. At the same time, the pressure is increased at 540℃ and the pressure is 10 MPa. After the process is completed, the pressure is stopped and the furnace is cooled to obtain an aluminum-magnesium composite material with an added Ti / Cu composite intermediate layer.

[0072] The aluminum-magnesium composite material with a Ti / Cu composite interlayer has an interfacial shear strength of 97.18 MPa.

[0073] Example 4

[0074] Other conditions are the same as in Example 1, except that a Ni / Cu composite intermediate layer is used, wherein the thickness of the pure Ni foil is 30 μm and the thickness of the Cu foil is 5 μm. This results in step (3) being stacked in the order of magnesium substrate / Cu foil / Ni foil / aluminum substrate, with the magnesium side on top of the sample, and placed into the graphite mold;

[0075] Steps (1) to (3) are the same as in Example 1, except that: the temperature is increased to 500℃ at 10℃ / min and held for 10 minutes, and then held at 500℃ for 1 hour. At the same time, the pressure is increased at 500℃ and the pressure is 10 MPa. After the process is completed, the pressure is stopped and the furnace is cooled to obtain an aluminum-magnesium composite material with Ni / Cu composite intermediate layer added.

[0076] The aluminum-magnesium composite material with added Ni / Cu composite interlayer has an interfacial shear strength of 53.78 MPa.

[0077] Comparative Example 1

[0078] Other conditions are the same as in Example 1, except that the heat preservation temperature in step (3) is 420℃ (420℃ is less than the eutectic reaction temperature of 450℃ between the Mg matrix and the Al foil interlayer), and only solid-phase diffusion occurs between Mg and the Al foil interlayer;

[0079] The resulting aluminum-magnesium composite material has an interfacial shear strength of only 15.38 MPa.

[0080] Comparative Example 2

[0081] The other conditions are the same as in Example 3, except that only a pure Ti foil with a thickness of 50 μm is added as an intermediate layer;

[0082] The Ti foil interlayer could not be bonded to the Mg matrix, making it impossible to successfully prepare aluminum-magnesium composite materials.

[0083] Comparative Example 3

[0084] All other conditions are the same as in Example 3, except that:

[0085] Step (3) Stack the magnesium substrate / Ti foil / Cu foil / aluminum substrate in the order of magnesium substrate / Ti foil / Cu foil / aluminum substrate, with the magnesium side on top of the sample, and place it into the graphite mold;

[0086] The obtained sample cracked at the interface, making it impossible to successfully prepare aluminum-magnesium composite material.

[0087] Comparative Example 4

[0088] Other conditions are the same as in Example 3, except that: the temperature is pressurized and kept at 450°C for 1 hour;

[0089] The Cu foil was not completely consumed at the interface, and the resulting aluminum-magnesium composite material had an interfacial shear strength of 7.87 MPa.

[0090] Comparative Example 5

[0091] All other conditions are the same as in Example 4, except that:

[0092] Pressurize and heat at 460℃ for 1 hour;

[0093] The obtained sample Cu foil was not completely consumed, and microcracks existed at the Ni foil / Cu foil interface, with a shear strength of only 6.16 MPa.

[0094] Comparative Example 6

[0095] The other conditions are the same as in Example 4, except that:

[0096] Pressurize and heat-hold at 520℃ for 1 hour;

[0097] At this point, due to the excessively high reaction temperature, both Cu foil and Ni were completely consumed. The hindering effect of Ni foil on the Al and Mg matrices disappeared, and a reaction began to occur between the Mg and Al matrices, making it impossible to successfully prepare aluminum-magnesium composite materials.

Claims

1. A method for preparing an aluminum / magnesium composite material with an added composite interlayer, characterized in that: First, aluminum alloy and magnesium alloy substrates are selected. Then, an intermediate layer is selected with an A / B structure. Before the reaction, one side of layer A is in contact with the aluminum alloy substrate and the other side is in contact with layer B, while the other side of layer B is in contact with the magnesium alloy substrate. At the reaction temperature, layer A remains intact, preventing direct diffusion between the aluminum alloy and magnesium alloy substrates and forming a good metallurgical bond with the aluminum alloy. At the reaction temperature, layer B and magnesium alloy form a eutectic liquid phase wetting interface, and under external pressure, excess liquid phase is squeezed out, while a new phase is generated, forming a metallurgical bond with both layer A and magnesium alloy.

2. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 1, characterized in that: The base aluminum alloy is selected from one of 2A12 aluminum alloy, 6061 aluminum alloy, 7075 aluminum alloy, and 5083 aluminum alloy, and the magnesium alloy is selected from one of AZ31 magnesium alloy, AZ91 magnesium alloy, ZK61 magnesium alloy, AM60 magnesium alloy, and WE43 magnesium alloy.

3. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 1, characterized in that: Includes the following steps, (1) The aluminum alloy and magnesium alloy substrates were prepared into layers, and the surfaces were cleaned with sandpaper and then ultrasonically cleaned with alcohol. (2) Select intermediate layer A and intermediate layer B with dimensions matching the size of the substrate, clean the surface with sandpaper and then clean with alcohol and ultrasonic cleaning. (3) Place the magnesium substrate / intermediate layer B / intermediate layer A / aluminum substrate stacked together, with the magnesium side at the top of the sample, and put it into the graphite mold; (4) Place the graphite mold containing the sample into the sintering furnace, set the heating program, perform hot-press diffusion connection under vacuum conditions, and cool with the furnace to obtain an aluminum-magnesium composite material with an added composite intermediate layer; the sintering temperature is higher than the eutectic reaction temperature of the Mg matrix and the contact intermediate layer, and lower than the eutectic reaction temperature of the Al matrix and the contact intermediate layer. or The sintering temperature is higher than the eutectic reaction temperature between the Al matrix and the contact intermediate layer, but lower than the eutectic reaction temperature between the Mg matrix and the contact intermediate layer; at the same time, the pressure is 0.01-20 MPa.

4. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 1, characterized in that: The aluminum alloy substrate, magnesium alloy substrate, intermediate layer A, and intermediate layer B are surface treated with 400-800 mesh wet sandpaper and then cleaned with alcohol in an ultrasonic cleaner for 5-10 minutes, 2-3 times.

5. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 1, characterized in that: The thickness of intermediate layer A should be set in a way that ensures its integrity during the reaction process; The thickness of the intermediate layer B should be set so that it is completely consumed by the eutectic reaction during the composite process, forming discontinuously distributed intermetallic compounds, precipitates, or solid solutions.

6. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 1, characterized in that: The intermediate layer A is selected from at least one of Ti, Cu, Ni, Al, Zn, Sn, and Ag. Intermediate layer B is selected from at least one of Ti, Cu, Ni, Al, Zn, Sn, and Ag, but the material of intermediate layer B is different from that of intermediate layer A.

7. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 6, characterized in that: Intermediate layer A / intermediate layer B is one of the Ni / Al, Ni / Cu, Ti / Al, Ti / Cu, or Ti / Ni structures.

8. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 1, characterized in that: The thickness of the magnesium substrate layer is greater than or equal to 0.1 mm; the thickness of the aluminum substrate layer is greater than or equal to 0.1 mm.

9. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 3, characterized in that: The vacuum condition mentioned in step (4) refers to a gas pressure inside the sintering furnace of less than 0.1 Pa; The sintering pressure in step (4) is 0.01-20 MPa.

10. The method for preparing an aluminum / magnesium composite material with an added composite interlayer according to claim 3, characterized in that: In step (4), the temperature is increased from room temperature to the sintering temperature at a heating rate of 5-10℃ / min.

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