Copper foil reinforced magnesium / aluminum composite plate and preparation process thereof

Abstract

The invention relates to the technical field of magnesium / aluminum layered composite materials, in particular to a copper foil reinforced magnesium / aluminum composite plate and a preparation process thereof. The preparation process comprises the following steps: respectively carrying out heat preservation heat treatment on a magnesium plate, an aluminum plate and a copper foil at different temperatures, then stacking the magnesium plate, the aluminum plate and the copper foil after the heat preservation heat treatment according to an aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate sequence, and immediately carrying out differential temperature rolling forming to form a magnesium / aluminum composite plate blank; and carrying out multi-pass hot rolling on the magnesium / aluminum composite plate blank to form the magnesium / aluminum composite plate. According to the method, the ultrathin copper foil is introduced into the interface, and differential temperature rolling and multi-pass hot rolling are combined, so that the interface bonding performance and the comprehensive mechanical performance of the magnesium / aluminum composite plate are effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium / aluminum layered composite materials, in particular to a copper foil reinforced magnesium / aluminum composite plate and a preparation process thereof. Background Art

[0002] Magnesium / aluminum composite plates have broad application prospects in aerospace, automotive, and transportation fields because they combine the excellent properties of magnesium alloys such as low density and high specific strength with the excellent properties of aluminum alloys such as good formability and high corrosion resistance.

[0003] However, research has found that during the hot working and subsequent heat treatment of magnesium / aluminum composite plates, a diffusion layer with a thickness of tens to hundreds of microns is easily formed on the interface, and its main component is the intermetallic compound Mg 17 Al 12 These intermetallic compounds are mainly Mg2Al3 and Mg2Al3, which are hard and brittle phases. These hard and brittle phases can easily become crack sources during the loading process of the composite plate, greatly weakening the strength and plasticity of the composite plate. Therefore, how to avoid the generation of a large number of intermetallic compounds at the interface of magnesium / aluminum composite plates has become a hot topic of research at home and abroad.

[0004] The study found that the introduction of metal powders on the magnesium / aluminum composite interface can significantly reduce the number of intermetallic compounds, thereby greatly improving the interface bonding strength of the composite plate. Providing a metal intermediate layer relative to the metal powder is more conducive to improving the performance of the composite plate. Specifically, the metal intermediate layer is easier to distribute evenly at the interface than the metal powder, and it is expected to give full play to the advantages of the metal intermediate layer in strengthening the composite interface.

[0005] Compared with other metals, copper has excellent toughness and good corrosion resistance, and is considered to be an ideal metal intermediate layer for magnesium / aluminum composite plates. Therefore, the copper intermediate layer is expected to improve the plastic deformation difference between the magnesium layer and the aluminum layer, realize the coordinated deformation of the magnesium layer and the aluminum layer during the deformation process, and thus improve the comprehensive mechanical properties of the magnesium / aluminum composite plate. However, there are many problems with using copper as an improved layer. For example, CN109174966A discloses a method of adding a transverse copper mesh and stacking at the interface of an aluminum alloy billet and a magnesium alloy billet, and adding a longitudinal copper mesh in the longitudinal direction of the stacked billet to form a combined billet, and realizing a three-dimensional mesh distribution of the copper layer after rolling deformation, and finally preparing an aluminum / copper / magnesium composite plate. This method requires pre-grooving and stacking on the magnesium alloy, the aluminum alloy and the transverse copper mesh, and then inserting the longitudinal copper mesh into the stacked billet slots. The process is cumbersome and is not conducive to large-scale batch production. CN112743083A discloses a method of adding a copper brazing material between magnesium powder and aluminum powder, and then preparing a magnesium / aluminum composite plate by hot pressing and compounding. However, this method is a powder metallurgy method for preparing magnesium / aluminum composite plates, which is costly and difficult to achieve large-scale application. CN108188523A discloses a method for preparing magnesium / aluminum layered composite plates by sputtering a copper layer on the surface of a magnesium plate and an aluminum plate, followed by hot pressing and sintering. However, the density and uniformity of the copper layer obtained by magnetron sputtering are difficult to accurately control, and Mg-Cu and Al-Cu intermetallic compounds are formed at the interface during the hot pressing and sintering process, which significantly weakens the interface bonding performance and comprehensive mechanical properties of the composite plate.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide a copper foil reinforced magnesium / aluminum composite plate and a preparation process thereof. The embodiment of the present invention provides a novel copper foil reinforced magnesium / aluminum composite plate preparation process which can improve the interface bonding performance and comprehensive mechanical properties of the magnesium / aluminum composite plate.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a process for preparing a copper foil reinforced magnesium / aluminum composite plate, comprising:

[0010] S1. Performing heat treatment at different temperatures on the magnesium plate, the aluminum plate and the copper foil, respectively. The heat preservation temperature of the magnesium plate is higher than that of the aluminum plate and the temperature difference between the two is 110-150° C., and the heat preservation temperature of the copper foil is lower than that of the aluminum plate and the temperature difference between the two is 60-100° C.;

[0011] S2, stacking the magnesium plate, aluminum plate and copper foil after the insulation heat treatment in S1 in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate, and then immediately performing differential temperature rolling to form a magnesium / aluminum composite slab;

[0012] S3, hot rolling the magnesium / aluminum composite slab for multiple passes to form a magnesium / aluminum composite plate.

[0013] In an optional embodiment, the insulation temperature of the magnesium plate in S1 is 400-480°C, the insulation temperature of the aluminum plate is 310-370°C, and the insulation temperature of the copper foil is 220-280°C.

[0014] In an optional implementation manner, in S1, the insulation time of the magnesium plate is 30-60 min, the insulation time of the aluminum plate is 20-30 min, and the insulation time of the copper foil is 5-10 min.

[0015] In an optional embodiment, the thickness ratio of the aluminum plate to the magnesium plate in S1 is (1:4)-(1:1), and the thickness of the copper foil is 0.005-0.15 mm.

[0016] In an optional embodiment, the heat preservation heat treatment of the magnesium plate, the aluminum plate and the copper foil in S1 is performed in a vacuum atmosphere with a vacuum degree of 0.5-5Pa.

[0017] In an optional embodiment, the deformation amount of the differential temperature rolling in S2 is 65-80%.

[0018] In an optional embodiment, the conditions for the multiple hot rolling in S3 include no less than 2 rolling passes; the conditions for each hot rolling pass include: temperature of 250-300°C, holding time of 5-10min, vacuum degree of 0.5-5Pa, and rolling deformation of 20-30% per pass.

[0019] In an optional embodiment, the magnesium plate in S1 is a Mg-Al-Zn or Mg-Zn-Zr magnesium alloy plate; the aluminum plate is a 5000 or 6000 series aluminum alloy plate; and the copper foil is a pure copper metal foil or a copper alloy foil.

[0020] In a second aspect, the present invention provides a copper foil reinforced magnesium / aluminum composite plate, which is prepared by the preparation process of the copper foil reinforced magnesium / aluminum composite plate of the aforementioned embodiment.

[0021] In an optional embodiment, the interface bonding of the magnesium / aluminum composite plate is good, and no intermetallic compound is formed between the magnesium layer and the copper layer and between the aluminum layer and the copper layer.

[0022] The present invention has the following beneficial effects: (1) By using different temperatures to keep the magnesium plate, aluminum plate and copper foil warm, it is helpful to give full play to the plastic deformation ability of the magnesium plate, aluminum plate and copper foil, so that a significant temperature gradient is formed between the magnesium plate, aluminum plate and copper foil, which is helpful to reduce the difference in deformation resistance between the magnesium plate, aluminum plate and copper foil during rolling, so that the magnesium plate, aluminum plate and copper foil obtain similar plastic deformation during differential temperature rolling. The introduction of ultra-thin copper foil can further realize the coordinated deformation of the magnesium plate and aluminum plate during rolling, weaken the texture strength of the composite plate, and improve the plastic forming ability of the magnesium / aluminum composite plate.

[0023] (2) The use of low-temperature and short-time heat preservation multi-pass rolling effectively inhibits the formation of intermetallic compounds at the interface of the magnesium / aluminum composite plate, greatly improving the interface bonding performance of the magnesium / aluminum composite plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 This is a SEM image of the interface of the copper foil reinforced magnesium / aluminum composite plate provided in Example 1 of the present invention;

[0026] Figure 2 The interface XRD pattern of the copper foil reinforced magnesium / aluminum composite plate provided in Example 1 of the present invention;

[0027] Figure 3 The interface EBSD image of the copper foil reinforced magnesium / aluminum composite plate provided in Example 1 of the present invention;

[0028] Figure 4 A texture strength diagram of a copper foil reinforced magnesium / aluminum composite plate provided in Example 1 of the present invention;

[0029] Figure 5 The interface EBSD image of the magnesium / aluminum composite plate provided in Comparative Example 1 of the present invention;

[0030] Figure 6 This is a texture strength diagram of the magnesium / aluminum composite plate provided for Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0032] In a first aspect, the present invention provides a process for preparing a copper foil reinforced magnesium / aluminum composite plate, comprising:

[0033] S1. Heat treatment;

[0034] The magnesium plate, aluminum plate and copper foil are subjected to insulation heat treatment at different temperatures respectively. The ultra-thin copper foil used in the present invention can further realize the coordinated deformation of the magnesium plate and the aluminum plate during rolling, weaken the texture strength of the magnesium / aluminum composite plate, and improve the plastic forming ability of the magnesium / aluminum composite plate.

[0035] The insulation temperature of the magnesium plate is higher than that of the aluminum plate and the temperature difference between the two is 110-150°C, for example, any value between 110°C, 120°C, 130°C, 140°C and 150°C.

[0036] The insulation temperature of the copper foil is lower than the insulation temperature of the aluminum plate and the temperature difference between the two is 60-100°C; for example, any value between 60-100°C, such as 60°C, 70°C, 80°C, 90°C and 100°C.

[0037] Specifically, the insulation temperature of the magnesium plate is 400-480° C., such as 400° C., 420° C., 450° C., 480° C., etc. The insulation time is 30-60 min., such as 30 min., 40 min., 50 min., 60 min., etc., etc.

[0038] The insulation temperature of the aluminum plate is 310-370° C., for example, 310° C., 320° C., 330° C., 340° C., 370° C., and any other value between 310-370° C. The insulation time is 20-30 min., for example, 20 min., 21 min., 22 min., 23 min., 24 min., 25 min., 26 min., 27 min., 28 min., 29 min., 30 min, and any other value between 20-30 min.

[0039] The insulation temperature of the copper foil is 220-280° C., such as 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., etc. The insulation time is 5-10 min., such as 5 min., 6 min., 7 min., 8 min., 9 min., 10 min., etc., etc., any value between 5-10 min.

[0040] By using different temperature insulation for magnesium plate, aluminum plate and copper foil, it is helpful to give full play to the plastic deformation capacity of magnesium plate, aluminum plate and copper foil, so that a significant temperature gradient is formed between the magnesium plate, aluminum plate and copper foil, which is beneficial to reduce the difference in deformation resistance between the magnesium plate, aluminum plate and copper foil during the rolling process, so that the magnesium plate, aluminum plate and copper foil obtain similar plastic deformation during the differential temperature rolling process.

[0041] Further, the thickness ratio of the aluminum plate to the magnesium plate is (1:4)-(1:1), for example, any value between (1:4)-(1:1) such as 1:1, 1:2, 1:3 and 1:4. Specifically, the thickness of the magnesium plate is 1-4 mm, for example, any value between 1 mm, 2 mm, 3 mm and 4 mm. The thickness of the copper foil is 0.005-0.15 mm, for example, any value between 0.005 mm, 0.01 mm, 0.05 mm, 0.1 mm and 0.15 mm.

[0042] The above-mentioned heat preservation heat treatment is carried out in a vacuum atmosphere, and the vacuum degree is 0.5-5 Pa, for example, any value between 0.5-5 Pa, such as 0.5 Pa, 1 Pa, 2 Pa, 3 Pa, 4 Pa ​​and 5 Pa. The embodiment of the present invention adopts a vacuum atmosphere for heat treatment, which can effectively avoid oxidation of the copper foil during the heat treatment process, is beneficial to the interface bonding of the composite plate during the rolling process, and further improves the comprehensive mechanical properties of the composite plate.

[0043] The magnesium plate is a Mg-Al-Zn or Mg-Zn-Zr magnesium alloy plate; the aluminum plate is a 5000 or 6000 aluminum alloy plate; and the copper foil is a pure copper metal foil or a copper alloy foil.

[0044] S2, differential temperature rolling;

[0045] The magnesium plate, aluminum plate and copper foil after the S1 insulation heat treatment are stacked in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate, and then immediately subjected to differential temperature rolling to form a magnesium / aluminum composite slab; wherein the deformation amount of the differential temperature rolling is 65-80%. Specifically, the deformation amount is any value between 65%, 70%, 75% and 80%, such as 65% and 80%.

[0046] S3, multi-pass hot rolling;

[0047] The magnesium / aluminum composite slab is subjected to multiple hot rolling passes to form a magnesium / aluminum composite plate. The rolling passes are not less than 2 times; the conditions of each hot rolling pass include: the temperature is 250-300°C, for example, any value between 250-300°C such as 250°C, 260°C, 270°C, 280°C, 290°C and 300°C. The holding time is 5-10min, for example, any value between 5min, 6min, 7min, 8min, 9min and 10min. The vacuum degree is 0.5-5Pa, for example, any value between 0.5-5Pa such as 0.5Pa, 1Pa, 2Pa, 3Pa, 4Pa and 5Pa.

[0048] The embodiment of the present invention effectively suppresses the formation of intermetallic compounds at the interface of the composite plate by adopting multi-pass rolling with low temperature and short-time heat preservation, thereby greatly improving the interface bonding performance of the composite plate.

[0049] In a second aspect, the present invention provides a copper foil reinforced magnesium / aluminum composite plate, which is prepared by the preparation process of the copper foil reinforced magnesium / aluminum composite plate of the aforementioned embodiment. The magnesium / aluminum composite plate has good interface bonding, and no intermetallic compounds are formed on both sides of the magnesium layer and the copper layer and the aluminum layer and the copper layer.

[0050] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0051] Example 1

[0052] This embodiment provides a preparation process of a copper foil reinforced magnesium / aluminum composite plate, comprising:

[0053] S1. Heat treatment;

[0054] The 1 mm thick 6082 aluminum plate, 0.035 mm thick copper foil and 4 mm thick AZ31 magnesium plate were subjected to insulation treatment at different temperatures and for different times, wherein the insulation temperature of the AZ31 magnesium plate was 430°C and the insulation time was 45 min, the insulation temperature of the 6082 aluminum plate was 310°C and the insulation time was 25 min, and the insulation temperature of the copper foil was 220°C and the insulation time was 6 min. The insulation treatments were all carried out in a heat treatment furnace with a vacuum degree of 1 Pa.

[0055] S2, differential temperature rolling;

[0056] After the heat preservation treatment, the magnesium plate, the aluminum plate and the copper foil are stacked in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate and then immediately subjected to differential temperature rolling, wherein the differential temperature rolling deformation amount is 65%.

[0057] S3, multi-pass hot rolling;

[0058] Subsequently, the prepared magnesium / aluminum composite plate was subjected to two hot rolling passes. The first hot rolling temperature was 280°C, the holding time was 10 minutes, the heat treatment vacuum was 2Pa, and the rolling deformation was 30%; the second hot rolling temperature was 250°C, the holding time was 6 minutes, the heat treatment vacuum was 3Pa, and the rolling deformation was 30%, and finally a copper foil reinforced magnesium / aluminum composite plate was obtained.

[0059] Characterization

[0060] The copper foil reinforced magnesium / aluminum composite plate of Example 1 was characterized, and the results are shown in Figures 1 to 4 .like Figure 1-4 As shown, the magnesium / aluminum composite plate has good interface bonding, the copper layer thickness is about 6.5μm, no intermetallic compounds are formed on both sides of the magnesium layer and the copper layer and the aluminum layer and the copper layer, the average grain size of the magnesium layer is 5μm, the texture strength of the magnesium layer is 9.57, and the texture strength of the aluminum layer is 3.36. The tensile strength of the magnesium / aluminum composite plate is 335MPa, the elongation is 15%, and the interface bonding strength is 90MPa.

[0061] Example 2

[0062] This embodiment provides a preparation process of a copper foil reinforced magnesium / aluminum composite plate, comprising:

[0063] S1. Heat treatment;

[0064] The 2 mm thick 6082 aluminum plate, 0.01 mm thick copper foil and 2 mm thick AZ31 magnesium plate were subjected to insulation treatment at different temperatures and for different times, wherein the insulation temperature of the AZ31 magnesium plate was 450°C and the insulation time was 30 min, the insulation temperature of the 6082 aluminum plate was 320°C and the insulation time was 25 min, and the insulation temperature of the copper foil was 240°C and the insulation time was 8 min. The insulation treatments were all carried out in a heat treatment furnace with a vacuum degree of 2 Pa.

[0065] S2, differential temperature rolling;

[0066] After the heat preservation treatment, the magnesium plate, the aluminum plate and the copper foil are stacked in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate and then immediately subjected to differential temperature rolling, wherein the differential temperature rolling deformation amount is 70%.

[0067] S3, multi-pass hot rolling;

[0068] Subsequently, the prepared magnesium / aluminum composite plate was subjected to three hot rolling passes, wherein the first hot rolling temperature was 300°C, the holding time was 6 minutes, the heat treatment vacuum was 2Pa, and the rolling deformation was 30%; the second hot rolling temperature was 280°C, the holding time was 6 minutes, the heat treatment vacuum was 2Pa, and the rolling deformation was 25%; the second hot rolling temperature was 250°C, the holding time was 6 minutes, the heat treatment vacuum was 2Pa, and the rolling deformation was 20%; and finally a copper foil reinforced magnesium / aluminum composite plate was obtained.

[0069] Characterization

[0070] The magnesium / aluminum composite plate provided in Example 2 has good interface bonding, the copper layer thickness is about 2 μm, no intermetallic compound is formed on both sides of the magnesium layer and the copper layer and the aluminum layer and the copper layer, the average grain size of the magnesium layer is 4.5 μm, the texture strength of the magnesium layer is 9.21, and the texture strength of the aluminum layer is 3.14. The tensile strength of the magnesium / aluminum composite plate is 344 MPa, the elongation is 16%, and the interface bonding strength is 80 MPa.

[0071] Example 3

[0072] This embodiment provides a preparation process of a copper foil reinforced magnesium / aluminum composite plate, comprising:

[0073] S1. Heat treatment;

[0074] 1mm thick 5052 aluminum plate, 0.1mm thick copper foil and 2mm thick ZK60 magnesium plate were subjected to insulation treatment at different temperatures and for different times, wherein the insulation temperature of the ZK60 magnesium plate was 420℃, the insulation time was 50min, the insulation temperature of the 5052 aluminum plate was 310℃, the insulation time was 25min, the insulation temperature of the copper foil was 240℃, the insulation time was 8min, and the insulation treatment was carried out in a heat treatment furnace with a vacuum degree of 1Pa.

[0075] S2, differential temperature rolling;

[0076] After the heat preservation treatment, the magnesium plate, the aluminum plate and the copper foil are stacked in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate and then immediately subjected to differential temperature rolling, wherein the differential temperature rolling deformation amount is 80%.

[0077] S3, multi-pass hot rolling;

[0078] Subsequently, the prepared magnesium / aluminum composite plate was subjected to three hot rolling passes, wherein the first hot rolling temperature was 300°C, the holding time was 8 minutes, the heat treatment vacuum was 1Pa, and the rolling deformation was 30%; the second hot rolling temperature was 280°C, the holding time was 8 minutes, the heat treatment vacuum was 1Pa, and the rolling deformation was 30%; the third hot rolling temperature was 260°C, the holding time was 8 minutes, the heat treatment vacuum was 1Pa, and the rolling deformation was 30%; and finally a copper foil reinforced magnesium / aluminum composite plate was obtained.

[0079] Characterization

[0080] The magnesium / aluminum composite plate provided in Example 3 has good interface bonding, the copper layer thickness is about 8 μm, no intermetallic compound is formed on both sides of the magnesium layer and the copper layer and the aluminum layer and the copper layer, the average grain size of the magnesium layer is 4.5 μm, the texture strength of the magnesium layer is 9.01, and the texture strength of the aluminum layer is 2.89. The tensile strength of the magnesium / aluminum composite plate is 356 MPa, the elongation is 18%, and the interface bonding strength is 85 MPa.

[0081] Comparative Example 1

[0082] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically consistent with the method for preparing a magnesium / aluminum composite plate provided in Example 1 in terms of operation and conditions, except that no copper foil is added between the magnesium plate and the aluminum plate.

[0083] The characterization results can be found in Figure 5 and 6 , the results are shown in Figure 5 and Figure 6 As shown, the average grain size of the magnesium layer of the composite plate is 9 μm, the texture strength of the magnesium layer is 10.48, and the texture strength of the aluminum layer is 4.13.

[0084] Comparative Example 2

[0085] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically consistent with the method for preparing a magnesium / aluminum composite plate provided in Example 1 in terms of operation and conditions, except that: subsequent multiple hot rolling is not performed.

[0086] The experimental results show that low-temperature, short-time multi-pass hot rolling is beneficial to the grain refinement of the magnesium layer and the aluminum layer in the composite plate, and significantly improves the interface bonding performance and mechanical properties of the magnesium / aluminum composite plate. The interface bonding performance and mechanical properties of the composite plate without subsequent low-temperature, short-time multi-pass rolling are poor.

[0087] Comparative Example 3

[0088] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically consistent with the method for preparing a composite plate provided in Example 1 in terms of operation and conditions, except that the thermal insulation treatment of the magnesium plate, aluminum plate and copper foil is carried out in a heat treatment furnace in an air atmosphere.

[0089] The experimental results show that copper foil is very easy to oxidize during the insulation process, resulting in weak bonding between the layers of the magnesium / aluminum composite plate, greatly reducing the interfacial bonding performance and comprehensive mechanical properties of the magnesium / aluminum composite plate.

[0090] Comparative Example 4

[0091] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically consistent with the method for preparing a magnesium / aluminum composite plate provided in Example 1 in terms of operation and conditions, except that the insulation temperatures of the magnesium plate and the aluminum plate are both 430°C.

[0092] The experimental results show that the plastic deformation capabilities of magnesium plates and aluminum plates at the same insulation temperature are quite different, making it difficult to achieve coordinated deformation of the two metals during rolling. This results in a large difference in the deformation amounts of the magnesium layer and the aluminum layer during rolling, which in turn significantly weakens the interface bonding properties and comprehensive mechanical properties of the magnesium / aluminum composite plate.

[0093] Comparative Example 5

[0094] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically consistent with the method for preparing a magnesium / aluminum composite plate provided in Example 1 in terms of operation and conditions, except that: the first hot rolling temperature of the magnesium / aluminum composite plate during multiple hot rolling is 400°C.

[0095] The experimental results show that when the magnesium / aluminum composite plate undergoes the first pass of 400°C hot rolling, obvious Mg-Cu and Al-Cu intermetallic compounds are formed at the interface. These hard and brittle intermetallic compounds are significantly broken during the subsequent second rolling process, greatly weakening the interface bonding performance and mechanical properties of the magnesium / aluminum composite plate.

[0096] Comparative Example 6

[0097] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically consistent with the method for preparing a magnesium / aluminum composite plate provided in Example 1 in terms of operation and conditions, except that the differential temperature rolling deformation is 30%.

[0098] The experimental results show that when the differential temperature rolling deformation is 30%, the magnesium layer and the copper layer, as well as the aluminum layer and the copper layer in the magnesium / aluminum composite plate are not well bonded, resulting in extremely poor interface bonding performance and mechanical properties of the magnesium / aluminum composite plate.

[0099] Comparative Example 7

[0100] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The operation and conditions of this method are basically the same as those of the method for preparing a magnesium / aluminum composite plate provided in Example 1, except that: the insulation treatment during the multi-pass hot rolling process of the magnesium / aluminum composite plate is carried out in an air heat treatment furnace.

[0101] The experimental results show that the copper layer of the magnesium / aluminum composite plate is very easy to be oxidized during the multi-pass rolling process, which greatly weakens the interfacial bonding performance of the composite plate, thereby further reducing the mechanical properties of the magnesium / aluminum composite plate.

[0102] The tensile mechanical properties and interface bonding properties of the magnesium / aluminum composite plates prepared in Comparative Examples 1-7 are shown in Table 1.

[0103] Table 1 Mechanical properties test of magnesium / aluminum composite plates of comparative examples 1-7

[0104] Sample Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 tensile strength 280MPa 263MPa 252MPa 265MPa 242MPa 240MPa 285MPa Elongation 10％ 11％ 6％ 9％ 5％ 6％ 12％ Interface shear strength 52MPa 45MPa 46MPa 50MPa 42MPa 35MPa 55MPa

[0105] According to Table 1, compared with Comparative Examples 1-7, the magnesium / aluminum composite plate prepared in the embodiment of the present invention has higher tensile strength, elongation and interface bonding strength, which indicates that the embodiment of the present invention effectively improves the interface bonding performance and comprehensive mechanical properties of the composite plate by introducing copper foil at the interface of the magnesium / aluminum composite plate and combining differential temperature rolling and low-temperature, short-time multi-pass hot rolling.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A process for preparing a copper foil reinforced magnesium / aluminum composite plate, characterized in that: include: S1. Performing heat treatment at different temperatures on the magnesium plate, the aluminum plate and the copper foil, respectively. The heat preservation temperature of the magnesium plate is higher than that of the aluminum plate and the temperature difference between the two is 110-150° C., and the heat preservation temperature of the copper foil is lower than that of the aluminum plate and the temperature difference between the two is 60-100° C.; S2, stacking the magnesium plate, aluminum plate and copper foil after the insulation heat treatment in S1 in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate, and then immediately performing differential temperature rolling to form a magnesium / aluminum composite slab; S3, hot rolling the magnesium / aluminum composite slab for multiple passes to form a magnesium / aluminum composite plate.

2. The preparation process according to claim 1, characterized in that: The insulation temperature of the magnesium plate in S1 is 400-480°C, the insulation temperature of the aluminum plate is 310-370°C, and the insulation temperature of the copper foil is 220-280°C.

3. The preparation process according to claim 1, characterized in that: In S1, the insulation time of the magnesium plate is 30-60 minutes, the insulation time of the aluminum plate is 20-30 minutes, and the insulation time of the copper foil is 5-10 minutes.

4. The preparation process according to any one of claims 1 to 3, characterized in that: In S1, the thickness ratio of the aluminum plate and the magnesium plate is (1:4)-(1:1), and the thickness of the copper foil is 0.005-0.15 mm.

5. The preparation process according to any one of claims 1 to 3, characterized in that: The heat preservation heat treatment of the magnesium plate, the aluminum plate and the copper foil in S1 is all carried out in a vacuum atmosphere with a vacuum degree of 0.5-5Pa.

6. The preparation process according to any one of claims 1 to 3, characterized in that: The deformation amount of differential temperature rolling in S2 is 65-80%.

7. The preparation process according to any one of claims 1 to 3, characterized in that: The conditions of the multi-pass hot rolling in S3 include no less than 2 rolling passes; the conditions of each hot rolling pass include: temperature of 250-300°C, holding time of 5-10min, vacuum degree of 0.5-5Pa, and deformation of each rolling pass of 20-30%.

8. The preparation process according to any one of claims 1 to 3, characterized in that: The magnesium plate in S1 is a Mg-Al-Zn or Mg-Zn-Zr magnesium alloy plate; the aluminum plate is a 5000 or 6000 aluminum alloy plate; and the copper foil is a pure copper metal foil or a copper alloy foil.

9. A copper foil reinforced magnesium / aluminum composite plate, characterized in that: The magnesium / aluminum composite plate is prepared by the preparation process of the copper foil reinforced magnesium / aluminum composite plate described in claim 1.

10. The copper foil reinforced magnesium / aluminum composite plate according to claim 9, characterized in that: The magnesium / aluminum composite plate has good interface bonding, and no intermetallic compounds are formed on both sides of the magnesium layer and the copper layer, and on both sides of the aluminum layer and the copper layer.

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