Preparation method of aluminum / magnesium composite material added with composite middle layer

Abstract

The invention relates to a preparation technology of an aluminum-magnesium layered composite material added with a composite middle layer, and belongs to the field of metal materials. The composite material is specifically composed of an aluminum alloy matrix layer, a composite middle layer and a magnesium alloy matrix layer. The specific preparation method comprises the following steps: selecting proper aluminum alloy and magnesium alloy matrixes; the aluminum substrate, the composite middle layer and the magnesium substrate are placed in a laminated mode; and the aluminum / magnesium layered composite material with light weight, high strength and good combination is obtained through vacuum hot-pressing diffusion bonding. The prepared aluminum matrix / composite interlayer / magnesium matrix composite combines the advantages of light weight and high strength of the aluminum matrix and the magnesium matrix, Ni / Al, Ti / Al, Ti / Cu and the like are innovatively selected as the composite interlayer, solid phase diffusion and instantaneous liquid phase diffusion on the two sides of the interlayer are synchronously achieved, and the prepared composite has the advantages of being high in metallurgical bonding strength, good in interface bonding, high in mechanical strength and the like. And the preparation process is clean and environment-friendly, is easy to control and can be used for large-scale production.

Description

Technical Field

[0001] The present invention relates to a preparation technology of an aluminum-magnesium laminated composite material with a composite intermediate layer, belonging to the field of metal materials. Background Art

[0002] As the lightest engineering metal material at present, Mg alloy is known as the "green engineering material of the 21st century". Magnesium alloy is widely used in the fields of aerospace and automotive industry due to its low density, high specific strength, good machinability and high damping capacity. However, magnesium alloy itself has poor corrosion resistance and poor plastic deformation ability, and is easy to brittle fracture. Therefore, in actual production, magnesium alloy is combined with aluminum alloy with better plasticity, good corrosion resistance and good welding performance to form a composite material, taking into account the excellent properties of both, further improving the comprehensive mechanical properties and broadening the application fields.

[0003] Common methods for preparing aluminum-magnesium composite materials at present include brazing method, diffusion bonding method, rolling cladding method, bimetallic composite casting method and friction stir welding and other preparation technologies. The brazing method selects a metal with a lower melting point as the filler metal. Utilizing the melting point temperature difference between the filler metal and the base metal, the filler metal is completely melted, and it wets and spreads on the surface of the base metal to undergo metallurgical bonding, thereby realizing the welding effect. The diffusion bonding method is a method that utilizes the free diffusion of atoms when different metals are in close contact under external action to realize the migration of surface atoms and carry out solid-state welding. The explosive cladding method uses a large amount of energy generated by explosion to cause the surfaces of the welded metals to undergo complex reactions such as high-speed collision, friction, interlocking, and diffusion, so that the metal surfaces are firmly bonded. Different from the previous several composite methods which are mainly solid-phase connections, the bimetallic casting composite method first melts the cladding metal liquid and then pours it onto the surface-treated base metal; or immerses the base metal in the cladding metal liquid, and promotes atomic diffusion by means of the energy released by liquid-phase cooling to form a continuous diffusion zone, thereby realizing the composite between dissimilar metals. The rolling cladding method generates a large amount of plastic deformation under rolling pressure, and the surface layers are activated and diffuse with each other and finally form metallurgical bonding.

[0004] Currently, the Al-Mg intermetallic compounds Al3Mg2 and Al 12 Mg 17 formed at the interface during the composite process are both brittle and hard, tend to brittle fracture, and have a large difference in thermal expansion coefficient from the matrix, and are prone to stress concentration and crack generation, resulting in poor bonding strength at the interface. The current solution is to add an intermediate layer to hinder the mutual diffusion between aluminum and magnesium, reduce the generation of brittle phases or change their distribution state. At the same time, the intermediate layer forms a solid solution or a new phase with better matching with the two-side matrix, so that the bonding strength is better. Such as the existing patent CN114769587A, an aluminum-magnesium laminated composite material with a Ni intermediate layer

[0005] It and its preparation method involve adding a nickel layer. This technology has obtained an aluminum-magnesium laminated composite material with a shear strength of 82-84 MPa for the first time. In order to further enhance the room-temperature shear strength of the aluminum-magnesium laminated composite material, the research group has conducted further research on the basis of CN114769587A, and thus formed the present invention. Summary of the Invention

[0006] The present invention provides a preparation method of an aluminum-magnesium composite material with a composite intermediate layer. By adding an intermediate layer with an A / B structure, the direct diffusion between magnesium and aluminum to form brittle intermetallic compounds is hindered, and at the same time, a new phase with better matching degree is generated, greatly improving the bonding performance of the interface of the aluminum-magnesium composite material, and obtaining an aluminum-magnesium composite material with good interfacial metallurgical bonding.

[0007] In the present invention, the main problems to be solved are as follows:

[0008] (1) How to coordinate the relationship between the interfacial bonding strength, sintering temperature, and holding time. When the sintering temperature is high and the holding time is long, a strong diffusion reaction occurs at the interface between the aluminum-magnesium matrix and the intermediate layer, resulting in the aggregation of a large amount of intermetallic compounds, making the interface layer too thick and affecting 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 part of the 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 good matching relationship, such as a coherent or semi-coherent relationship, so as to ensure good interfacial metallurgical bonding.

[0010] To solve the above problems and obtain an aluminum-magnesium composite material with good interfacial bonding, on the basis of a large number of exploratory experiments, the following solutions are proposed, including the selection of aluminum and magnesium matrices, the selection of the intermediate layer, and the diffusion bonding of the aluminum alloy matrix / intermediate layer / magnesium alloy matrix.

[0011] A preparation method of an aluminum / magnesium composite material with a composite intermediate layer according to the present invention first selects an aluminum alloy matrix and a magnesium alloy matrix, and then selects an intermediate layer. The structure of the intermediate layer is an A / B structure. Before the reaction, one side of A contacts the aluminum alloy matrix and the other side contacts B, and the other side of B contacts the magnesium alloy matrix; at the reaction temperature, the A layer remains intact, preventing the direct diffusion between the aluminum alloy matrix and the magnesium alloy matrix, and forming a good metallurgical bond with the aluminum alloy; at the reaction temperature, the B layer generates a eutectic liquid phase to wet the interface with the magnesium alloy, and under the action of an external pressure, the excess liquid phase is extruded, and at the same time, a new phase is generated, forming a metallurgical bond with both the A layer and the magnesium alloy.

[0012] When applied industrially, the grades of the matrix aluminum alloy and magnesium alloy can be selected according to requirements. The matrix aluminum alloy is selected from one of 2A12 aluminum alloy, 6061 aluminum alloy, 7075 aluminum alloy, 5083 aluminum alloy, etc. The above aluminum alloys can meet the requirements of strength, corrosion resistance, weldability, etc.

[0013] The magnesium alloy is selected from one of AZ31 magnesium alloy, AZ91 magnesium alloy, ZK61 magnesium alloy, AM60 magnesium alloy, WE43 magnesium alloy, etc. The above magnesium alloys can meet the requirements of strength, plasticity, damping, etc. The matrix can be prepared by methods such as as-cast state, deformed state, 3D printing or powder metallurgy method, and is specifically selected according to the alloy grade.

[0014] Basis for the selection of the intermediate layer: While the intermediate layer hinders the diffusion between aluminum and magnesium, it forms intermetallic compounds and solid solutions with the matrix, and generates new phases to form good metallurgical bonding with the matrix. Specifically, intermediate layer high-melting-point metals such as Ti, Ag, and Ni have less dissolution and diffusion, can maintain the integrity of the intermediate layer, effectively prevent the large diffusion of aluminum and magnesium elements, and prevent the formation of a large amount of hard and brittle aluminum-magnesium intermetallic compounds. In addition, a new interface layer is generated, improving the bonding strength of the interface. Metals such as Cu, Al, Sn, and Zn form a large number of new phases with the matrix and further react with the high-melting-point intermediate layer to achieve good bonding on both sides. In addition, rare earth (RE) elements have strong metallicity, are easy to combine with other metal elements to form rare earth precipitates, and have the effects of refinement strengthening and second-phase precipitation strengthening, thus strengthening the interface. Select two or more of the above intermediate layers according to requirements to form a composite intermediate layer. For example, Ni / Al, Ti / Al, Ti / Cu, etc. are selected as the composite intermediate layer, which not only ensures the integrity of the interface layer but also forms good metallurgical bonding with the matrix.

[0015] When Ni / Al, Ti / Al, Ti / Cu, etc. are selected as the composite intermediate layer, it can hinder the direct diffusion between magnesium and aluminum to generate brittle intermetallic compounds, and at the same time generate new phases with better matching degree, greatly improving the bonding performance of the interface of the aluminum-magnesium composite material, and obtaining an aluminum-magnesium composite material with good interfacial metallurgical bonding.

[0016] The diffusion bonding technical solution for preparing the aluminum-magnesium composite material with a composite intermediate layer of the present invention is as follows:

[0017] (1) Prepare the aluminum alloy and magnesium alloy matrixes into layers respectively, and perform surface cleaning treatment with sandpaper, and then ultrasonically wash with alcohol;

[0018] (2) Select intermediate layer A and intermediate layer B with sizes matching the matrix according to the size of the matrix, perform surface cleaning treatment with sandpaper and then ultrasonically wash with alcohol;

[0019] (3) Stack them in the order of magnesium matrix / intermediate layer B / intermediate layer A / aluminum matrix, with the magnesium side on the top of the sample, and then place them into a graphite mold.

[0020] (4) Put the graphite mold with the sample into a sintering furnace, set the heating program, and conduct hot pressing diffusion bonding under vacuum conditions, then cool it with the furnace to obtain an aluminum-magnesium composite material with a composite intermediate layer. The sintering temperature of the hot pressing diffusion bonding 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, and lower than the eutectic reaction temperature of the Mg matrix and the intermediate layer.

[0023] Preferably, the aluminum alloy matrix, magnesium alloy matrix, intermediate layer A, and intermediate layer B are surface-treated with 400-mesh to 800-mesh water sandpaper, and then cleaned with alcohol in an ultrasonic cleaner for 5 - 10 minutes, 2 - 3 times. To further improve the product quality, after alcohol cleaning, it is placed in a vacuum environment to dry naturally.

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

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

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

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

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

[0029] Intermediate layer A / intermediate layer B can preferably be one of the structures such as Ni / Al, Ti / Al, Ti / Cu, Ti / Cu, Ti / Ni, etc. That is, if intermediate layer A is Ni, the corresponding intermediate layer B is Al or Cu; if intermediate layer A is Ti, the corresponding intermediate layer B is Al or Cu or Ni.

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

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

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

[0033] Preferably, in step (4), the vacuum condition means that the air pressure in the sintering furnace is less than 0.1 Pa, and more preferably the air pressure in the furnace is less than 0.01 Pa;

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

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

[0036] Adopting the above - mentioned gradient heating sintering process can better control the heating rate and temperature deviation during sintering, enable sufficient diffusion between the aluminum - magnesium matrix and the intermediate layer, and make the interface combination tight.

[0037] During practical industrial applications, stack and place them in the order of magnesium matrix / Al foil / Ni foil / aluminum matrix, with the magnesium side at the top of the sample, and put them into a graphite mold;

[0038] Put the graphite mold with the sample into a vacuum sintering furnace, evacuate to 2*10 -2 Pa and then start heating. First, heat to 460 °C at a rate of 10 °C / min and hold for 10 minutes, hold at 460 °C for 1 hour, and at the same time start pressurizing at 460 °C with a pressure of 10 MPa. After the process ends, stop pressurizing and cool with the furnace to obtain the aluminum - magnesium composite material with a Ni / Al composite intermediate layer added.

[0039] During practical industrial applications, stack and place them in the order of magnesium matrix / Al foil / Ti foil / aluminum matrix, with the magnesium side at the top of the sample, and put them into a graphite mold;

[0040] Put the graphite mold with the sample into a vacuum sintering furnace, evacuate to 2*10 -2Start heating after reaching [Pa], increase the temperature to 550 °C at a rate of 10 °C / min and hold for 10 minutes, hold at 550 °C for 1 hour, start applying pressure at 550 °C with a pressure of 10 MPa, stop applying pressure after the process is completed and cool with the furnace to obtain an aluminum-magnesium composite material with a Ti / Al composite intermediate layer.

[0041] When applied in actual industry, stack and place them in the order of magnesium matrix / Cu foil / Ti foil / aluminum matrix, with the magnesium side at the top of the sample, put them into a graphite mold, and place the graphite mold with the sample into a vacuum sintering furnace, evacuate to 2*10 -2 Start heating after reaching [Pa], increase the temperature to 540 °C at a rate of 10 °C / min and hold for 10 minutes, hold at 540 °C for 1 hour, start applying pressure at 540 °C with a pressure of 10 MPa, stop applying pressure after the process is completed and cool with the furnace to obtain an aluminum-magnesium composite material with a Ti / Cu composite intermediate layer.

[0042] This patent selects Ni / Al, Ti / Al, Ti / Cu, etc. as composite intermediate layers, which not only hinder the direct diffusion between aluminum and magnesium to form intermetallic compounds through high-melting-point Ti and Ni, but also change the phase composition at the interface, generate new phases at the interface, and realize the composite of aluminum-magnesium materials.

[0043] In the present invention, the principle for setting the thickness of intermediate layer A is to ensure its integrity during the reaction process; the principle for setting the thickness of intermediate layer B is to be completely consumed through eutectic reaction, etc. during the composite process, and form discontinuously distributed intermetallic compounds, precipitates or solid solutions. Generally speaking, the thickness of the metal foil layer is greater than 1 μm, and the thickness range of the electroplated metal layer is 0.1 μm - 50 μm.

[0044] The shear strength of the aluminum-magnesium composite material obtained by the present invention reaches 80 - 130 MPa.

[0045] When applied in industry, at the sintering temperature, intermediate layer B is made to completely react into intermetallic compounds by controlling the time, but at this time, intermediate layer A must still be continuously attached to the aluminum matrix and form a metallurgical bond with the aluminum matrix.

[0046] The principle of the present invention:

[0047] The present invention effectively prevents the direct contact between the aluminum-magnesium matrix to generate brittle intermetallic compounds by adding a composite intermediate layer. While ensuring good metallurgical bonding between Ti or Ni, etc. and the Al side, metals such as Al and Cu are added on the Mg side to react with the Mg side to generate new phases with better bonding, greatly improving the bonding strength on the Mg side. Through many experimental studies and improvements, Ni / Al, Ti / Al, Ti / Cu, etc. are selected as the composite intermediate layer, and the preparation of aluminum-magnesium composites with a composite intermediate layer is successfully achieved under different sintering temperatures and pressures, significantly enhancing its shear strength.

[0048] Advantages of the present invention:

[0049] 1. This process is easy to operate, significantly reducing production costs and having high economic benefits;

[0050] 2. The thickness of the added composite intermediate layer is very small, having little impact on the overall quality;

[0051] 3. The selection range of the added composite intermediate layer is wide. The present invention is applicable to the preparation of various alloy matrix / intermediate layer / alloy matrix composites. The components of the alloy matrix and the intermediate layer can be selected according to actual needs, with flexible composition regulation and wide application fields. Description of the Drawings

[0052] Attached Figure 1 is the interfacial microstructure of the aluminum-magnesium composite material with a Ni / Al composite intermediate layer added in Example 1;

[0053] Attached Figure 2 is the interfacial microstructure of the aluminum-magnesium composite material with a Ti / Al composite intermediate layer added in Example 2;

[0054] Attached Figure 3 is the interfacial microstructure of the aluminum-magnesium composite material with a Ti / Cu composite intermediate layer added in Example 3;

[0055] Attached Figure 4 is the interfacial microstructure of the aluminum-magnesium composite material with a Ni / Cu composite intermediate layer added in Example 4;

[0056] Attached Figure 5 is the interfacial microstructure of the aluminum-magnesium composite material with a Ni / Al composite intermediate layer added in Comparative Example 1;

[0057] Attached Figure 6 is the interfacial microstructure of the aluminum-magnesium composite material with a Ni / Cu composite intermediate layer added in Comparative Example 5;

[0058] Attached Figure 7 is the interfacial microstructure of the aluminum-magnesium composite material with a Ni / Cu composite intermediate layer added in Comparative Example 6 Detailed Embodiments

[0059] Example 1:

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

[0061] (2) The pure Ni foil with a thickness of 30 μm and the pure Al foil with a thickness of 15 μm were cut into discs with a diameter of 40 mm and cleaned together with the substrate.

[0062] (3) Stacked and placed in the order of magnesium substrate / Al foil / Ni foil / aluminum substrate, with the magnesium side at the top of the sample, and put into a graphite mold.

[0063] (4) The graphite mold loaded with the sample was placed in a vacuum sintering furnace, evacuated to 2×10 -2 Pa and then heated. It was heated to 460 °C at a rate of 10 °C / min and held for 10 minutes, held at 460 °C for 1 hour, and at the same time, pressurization started at 460 °C with a pressure of 10 MPa. After the process ended, the pressurization was stopped and the furnace was cooled, obtaining an aluminum-magnesium composite material with an added Ni / Al composite interlayer.

[0064] In Example 1, the interface layer of the aluminum-magnesium composite material prepared with the Ni / Al composite interlayer was dense. After sintering and hot pressing, the Al-Mg intermetallic compound decreased and mainly existed in the form of precipitated phases. A large number of new phases Al3Ni2 were generated at the interface, which was well combined with both the Ni interlayer and the Mg side. The shear strength of the obtained aluminum-magnesium composite material reached 127.76 MPa, much higher than the 20 - 30 MPa of general aluminum-magnesium composite materials.

[0065] Example 2

[0066] Other conditions were the same as those in Example 1, except that: a Ti / Al composite interlayer was used, where the thickness of the pure Ti foil was 50 μm and the thickness of the Al foil was 15 μm. This led to the stacking and placement in the order of magnesium substrate / Al foil / Ti foil / aluminum substrate in step (3), with the magnesium side at the top of the sample, and put into a graphite mold.

[0067] Steps (1) to (3) were the same as those in Example 1, except that: it was heated to 550 °C at a rate of 10 °C / min and held for 10 minutes, held at 550 °C for 1 hour, and at the same time, pressurization started at 550 °C with a pressure of 10 MPa. After the process ended, the pressurization was stopped and the furnace was cooled, obtaining an aluminum-magnesium composite material with an added Ti / Al composite interlayer.

[0068] The aluminum-magnesium composite material with a 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 interlayer is used, where the thickness of the pure Ti foil is 30 μm and the thickness of the Cu foil is 10 μm. This results in stacking in the order of magnesium matrix / Cu foil / Ti foil / aluminum matrix in step (3), with the magnesium side at the top of the sample, and placing it into a graphite mold;

[0071] Steps (1) to (3) are the same as in Example 1, except that it is heated to 540 °C at a rate of 10 °C / min and held for 10 minutes, held at 540 °C for 1 hour, and at the same time, pressure is applied starting from 540 °C, with the pressure magnitude being 10 MPa. After the process ends, the pressure is stopped and it is cooled with the furnace to obtain an aluminum-magnesium composite material with a Ti / Cu composite interlayer.

[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 interlayer is used, where the thickness of the pure Ni foil is 30 μm and the thickness of the Cu foil is 5 μm. This results in stacking in the order of magnesium matrix / Cu foil / Ni foil / aluminum matrix in step (3), with the magnesium side at the top of the sample, and placing it into a graphite mold;

[0075] Steps (1) to (3) are the same as in Example 1, except that it is heated to 500 °C at a rate of 10 °C / min and held for 10 minutes, held at 500 °C for 1 hour, and at the same time, pressure is applied starting from 500 °C, with the pressure magnitude being 10 MPa. After the process ends, the pressure is stopped and it is cooled with the furnace to obtain an aluminum-magnesium composite material with a Ni / Cu composite interlayer.

[0076] The aluminum-magnesium composite material with a 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 holding temperature in step (3) is 420 °C (420 °C is less than the eutectic reaction temperature of 450 °C between the Mg matrix and the Al foil interlayer), and only solid-phase diffusion occurs in the Mg and Al foil interlayer;

[0079] The interfacial shear strength of the obtained aluminum-magnesium composite material is only 15.38 MPa.

[0080] Comparative Example 2

[0081] Other conditions were the same as those in Example 3, except that only a pure Ti foil with a thickness of 50 μm was added as the intermediate layer;

[0082] The Ti foil intermediate layer could not be connected to the Mg matrix, and the aluminum-magnesium composite material could not be successfully prepared.

[0083] Comparative Example 3

[0084] Other conditions were the same as those in Example 3, except that:

[0085] In step (3), the layers were stacked in the order of magnesium matrix / Ti foil / Cu foil / aluminum matrix, and the magnesium side was located at the top of the sample, and then placed into the graphite mold;

[0086] Cracking occurred at the interface of the obtained sample, and the aluminum-magnesium composite material could not be successfully prepared.

[0087] Comparative Example 4

[0088] Other conditions were the same as those in Example 3, except that pressure was applied and heat was kept for 1 hour at 450 °C;

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

[0090] Comparative Example 5

[0091] Other conditions were the same as those in Example 4, except that:

[0092] Pressure was applied and heat was kept for 1 hour at 460 °C;

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

[0094] Comparative Example 6

[0095] Other conditions were the same as those in Example 4, except that:

[0096] Pressure was applied and heat was kept for 1 hour at 520 °C;

[0097] At this time, due to the too high reaction temperature, both the Cu foil and Ni were completely consumed, the hindering effect of the Ni foil between the Al matrix and the Mg matrix disappeared, and the reaction between the Mg and Al matrices began, and the aluminum-magnesium composite material could not be successfully prepared.

Claims

1. A method for preparing an aluminum / magnesium composite material with a composite intermediate layer, characterized in that: First, select an aluminum alloy matrix and a magnesium alloy matrix, and then select an intermediate layer. The structure of the intermediate layer is an A / B structure. Before the reaction, one side of A contacts the aluminum alloy matrix and the other side contacts B, and the other side of B contacts the magnesium alloy matrix; at the reaction temperature, the A layer remains intact, preventing the direct mutual diffusion of the aluminum alloy matrix and the magnesium alloy matrix, and forming a good metallurgical bond with the aluminum alloy; at the reaction temperature, the B layer generates a eutectic liquid phase to wet the interface with the magnesium alloy, and the excess liquid phase is extruded under the action of an external pressure. At the same time, a new phase is generated, forming a metallurgical bond with both the A layer and the magnesium alloy.

2. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 1, characterized in that: The matrix aluminum alloy is selected from one of 2A12 aluminum alloy, 6061 aluminum alloy, 7075 aluminum alloy, 5083 aluminum alloy, etc., and the magnesium alloy is selected from one of AZ31 magnesium alloy, AZ91 magnesium alloy, ZK61 magnesium alloy, AM60 magnesium alloy, WE43 magnesium alloy, etc.

3. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 1, characterized in that: It includes the following steps: (1) Prepare the aluminum alloy and the magnesium alloy matrix into layers respectively, and perform surface cleaning treatment with sandpaper, and then ultrasonically wash with alcohol. (2) Select intermediate layer A and intermediate layer B with sizes matching the matrix size according to the size of the matrix, perform surface cleaning treatment with sandpaper and then ultrasonically wash with alcohol. (3) Stack and place them in the order of magnesium matrix / intermediate layer B / intermediate layer A / aluminum matrix, with the magnesium side at the top of the sample, and put them into a graphite mold. (4) Put the graphite mold filled with the sample into a sintering furnace, set the heating program, perform hot pressing diffusion bonding under vacuum conditions, and cool with the furnace to obtain an aluminum-magnesium composite material with a composite intermediate layer; the sintering temperature is higher than the eutectic reaction temperature between the Mg matrix and the contacting intermediate layer and lower than the eutectic reaction temperature between the Al matrix and the contacting intermediate layer. Or The sintering temperature is higher than the eutectic reaction temperature between the Al matrix and the contacting intermediate layer and lower than the eutectic reaction temperature between the Mg matrix and the contacting intermediate layer. At the same time, apply a pressure of 0.01 - 20 MPa.

4. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 1, characterized in that: The aluminum alloy matrix, the magnesium alloy matrix, intermediate layer A, and intermediate layer B are surface-treated with 400 - 800 - mesh water sandpaper and cleaned with alcohol in an ultrasonic cleaner for 5 - 10 minutes, 2 - 3 times. To further improve the quality of the product, after alcohol cleaning, it is placed in a vacuum environment and dried naturally.

5. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 1, characterized in that: The thickness setting principle of intermediate layer A is to ensure its integrity during the reaction process. The thickness setting principle of intermediate layer B is to be completely consumed through eutectic reaction, etc. during the composite process, and form discontinuously distributed intermetallic compounds, precipitates, or solid solutions.

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

7. According to the preparation method of an aluminum / magnesium composite material with a composite intermediate layer as described in claim 6, it is characterized in that: Intermediate layer A / intermediate layer B is one of the structures such as Ni / Al, Ni / Cu, Ti / Al, Ti / Cu, Ti / Ni, etc.

8. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 1, characterized in that: The thickness of the magnesium matrix layer is greater than or equal to 0.1 mm, which of course includes thickness schemes in series such as 2 - 15 mm, 20 - 10 mm, etc.; the thickness of the aluminum matrix layer can be greater than or equal to 0.1 mm, which of course includes thickness schemes in series such as 2 - 15 mm, 20 - 10 mm, etc.

9. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 3, characterized in that: The vacuum condition described in step (4) means that the air pressure in the sintering furnace is less than 0.1 Pa, and more preferably, the air pressure in the furnace is less than 0.01 Pa; The pressure for sintering in step (4) is 0.01 - 20 MPa, and more preferably 8 - 15 MPa.

10. The preparation method of an aluminum / magnesium composite material with a composite intermediate layer added according to claim 3, characterized in that: The heating process described in step (4) is: heating from room temperature to the sintering temperature at a heating rate of 5 - 10 °C / min.

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