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

Abstract

The present invention relates to the technical field of magnesium / aluminum layered composite materials, and more specifically, to a copper foil-reinforced magnesium / aluminum composite plate and a preparation process thereof. The preparation process comprises: subjecting a magnesium plate, an aluminum plate, and a copper foil to respective heat treatments at different temperatures, and then stacking the magnesium plate, aluminum plate, and copper foil after the heat treatments in the order of aluminum plate / copper foil / magnesium plate / copper foil / aluminum plate, followed by immediate differential temperature rolling to form a magnesium / aluminum composite slab; and subjecting the magnesium / aluminum composite slab to multiple hot rolling passes to form a magnesium / aluminum composite plate. The present invention effectively improves the interface bonding performance and comprehensive mechanical properties of the magnesium / aluminum composite plate by introducing an ultra-thin copper foil at the interface and combining differential temperature rolling with multiple hot rolling passes.

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 thermal processing 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 The main components of the intermetallic compounds are Mg2Al3 and Mg2Al3. These intermetallic compounds 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 formation of large amounts of intermetallic compounds at the interface of magnesium / aluminum composite plates has become a hot research topic both at home and abroad.

[0004] Research has found that introducing metal powder at the magnesium / aluminum composite interface can significantly reduce the amount of intermetallic compounds, thereby greatly improving the interfacial bonding strength of the composite plate. The presence of a metal interlayer relative to the metal powder is even more beneficial for improving the performance of the composite plate. Specifically, the metal interlayer is more easily distributed at the interface than the metal powder, potentially leveraging its strength to strengthen the composite interface.

[0005] Compared with other metals, copper has excellent toughness and good corrosion resistance and is considered 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, achieve synergistic deformation of the magnesium layer and the aluminum layer during deformation, and thus improve the comprehensive mechanical properties of the magnesium / aluminum composite plate. However, the use of copper as an improved layer also has many problems. For example, CN109174966A discloses a method of adding a transverse copper mesh at the interface of an aluminum alloy billet and a magnesium alloy billet and stacking them, and adding a longitudinal copper mesh in the longitudinal direction of the stacked billets to form a combined billet. After rolling deformation, a three-dimensional mesh distribution of the copper layer is achieved, and finally an aluminum / copper / magnesium composite plate is prepared. This method requires pre-slotting the magnesium alloy, aluminum alloy and transverse copper mesh and then stacking them. The longitudinal copper mesh is then inserted into the stacked billet slots. The process is cumbersome and not conducive to large-scale batch production. CN112743083A discloses a method of adding a copper brazing filler metal between magnesium powder and aluminum powder and then preparing a magnesium / aluminum composite plate by hot pressing. However, this method uses powder metallurgy to prepare 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 precisely control, and Mg-Cu and Al-Cu intermetallic compounds are formed at the interface during the hot pressing and sintering process, significantly weakening 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 present invention aims to provide a copper foil reinforced magnesium / aluminum composite plate and its preparation process. The present invention provides a novel copper foil reinforced magnesium / aluminum composite plate preparation process that 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 on a magnesium plate, an aluminum plate, and a copper foil at different temperatures, wherein the magnesium plate is held at a higher temperature than the aluminum plate and the temperature difference therebetween is 110-150° C., and the copper foil is held at a lower temperature than the aluminum plate and the temperature difference therebetween 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 in 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 embodiment, the insulation time of the magnesium plate in S1 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.

[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 multi-pass 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 5-10 minutes, 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 temperature insulation for the magnesium plate, aluminum plate and copper foil, 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 conducive to reducing 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 can obtain similar plastic deformation during the differential temperature rolling process. The introduction of ultra-thin copper foil can further achieve the coordinated deformation of the magnesium plate and aluminum plate during the rolling process, 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 multi-pass rolling with low temperature and short-time insulation effectively inhibits the formation of intermetallic compounds at the interface of magnesium / aluminum composite plates, greatly improving the interface bonding performance of magnesium / aluminum composite plates. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any 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 This is an EBSD image of the interface of the copper foil reinforced magnesium / aluminum composite plate provided in Example 1 of the present invention;

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

[0029] Figure 5 This is an EBSD image of the interface 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 in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are 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 use of ultra-thin copper foil in the present invention can further achieve the coordinated deformation of the magnesium plate and the aluminum plate during the rolling process, 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 110-150°C, such as 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, it is any value between 60-100°C, such as 60°C, 70°C, 80°C, 90°C and 100°C.

[0037] Specifically, the holding temperature of the magnesium plate is 400-480° C., such as any value between 400° C., 420° C., 450° C., and 480° C. The holding time is 30-60 minutes, such as any value between 30 minutes, 40 minutes, 50 minutes, and 60 minutes.

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

[0039] The copper foil has a holding temperature of 220-280° C., for example, 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., and any other value between 220-280° C. The holding time is 5-10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, and any other value between 5-10 minutes.

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

[0042] The above-mentioned heat preservation heat treatment is all carried out in a vacuum atmosphere with a vacuum degree of 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 prevent oxidation of the copper foil during the heat treatment process, facilitate the interface bonding of the composite plate during the rolling process, and thus improve 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 series 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. The deformation amount of the differential temperature rolling is 65-80%. Specifically, the deformation amount is any value between 65% and 80%, such as 65%, 70%, 75%, 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 at least two, and the hot rolling conditions for each pass include: a temperature of 250-300°C, such as any value between 250°C and 300°C, for example, 250°C, 260°C, 270°C, 280°C, 290°C, and 300°C; a holding time of 5-10 minutes, such as any value between 5-10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, and 10 minutes; and a vacuum level of 0.5-5 Pa, such as any value between 0.5-5 Pa, for example, 0.5 Pa, 1 Pa, 2 Pa, 3 Pa, 4 Pa, and 5 Pa.

[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 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, produced using the process for producing a copper-foil-reinforced magnesium / aluminum composite plate described in the aforementioned embodiment. The magnesium / aluminum composite plate exhibits good interfacial bonding, with no intermetallic compounds forming between the magnesium layer and the copper layer, or between the aluminum layer and the copper layer.

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

[0051] Example 1

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

[0053] S1. Heat treatment;

[0054] A 1 mm thick 6082 aluminum plate, a 0.035 mm thick copper foil and a 4 mm thick AZ31 magnesium plate were subjected to insulation treatment at different temperatures and times, respectively. 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. The insulation temperature of the copper foil was 220°C and the insulation time was 6 min. The insulation treatment was 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, aluminum plate and 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] The prepared magnesium / aluminum composite plate was then 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%, finally obtaining a copper foil reinforced magnesium / aluminum composite plate.

[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 interfacial bonding. The copper layer is approximately 6.5 μm thick, and no intermetallic compounds form between the magnesium and copper layers, or between the aluminum and copper layers. The average grain size of the magnesium layer is 5 μm, and the texture strength of the magnesium layer is 9.57, while the texture strength of the aluminum layer is 3.36. The magnesium / aluminum composite plate has a tensile strength of 335 MPa, an elongation of 15%, and an interfacial bonding strength of 90 MPa.

[0061] Example 2

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

[0063] S1. Heat treatment;

[0064] A 2 mm thick 6082 aluminum plate, a 0.01 mm thick copper foil and a 2 mm thick AZ31 magnesium plate were subjected to insulation treatment at different temperatures and times, respectively. 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, aluminum plate and 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] The prepared magnesium / aluminum composite plate was then subjected to three hot rolling passes. 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 exhibited good interfacial bonding. The copper layer was approximately 2 μm thick, with no intermetallic compounds forming between the magnesium and copper layers, or between the aluminum and copper layers. The average grain size of the magnesium layer was 4.5 μm, and the texture strength of the magnesium layer was 9.21, while that of the aluminum layer was 3.14. The magnesium / aluminum composite plate had a tensile strength of 344 MPa, an elongation of 16%, and an interfacial bonding strength of 80 MPa.

[0071] Example 3

[0072] This embodiment provides a process for preparing 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 times, respectively. The insulation temperature of ZK60 magnesium plate was 420℃ and the insulation time was 50min, the insulation temperature of 5052 aluminum plate was 310℃ and the insulation time was 25min, and the insulation temperature of copper foil was 240℃ and the insulation time was 8min. 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, aluminum plate and 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] The prepared magnesium / aluminum composite plate was then subjected to three hot rolling passes. 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 exhibited good interfacial bonding. The copper layer was approximately 8 μm thick, and no intermetallic compounds formed between the magnesium and copper layers, or between the aluminum and copper layers. The average grain size of the magnesium layer was 4.5 μm, and the texture strength of the magnesium layer was 9.01, while that of the aluminum layer was 2.89. The magnesium / aluminum composite plate had a tensile strength of 356 MPa, an elongation of 18%, and an interfacial bonding strength of 85 MPa.

[0081] Comparative Example 1

[0082] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is basically the same as 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 substantially 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] Experimental results show that low-temperature, short-duration, multi-pass hot rolling promotes grain refinement in the magnesium and aluminum layers of the composite plate, significantly improving the interfacial bonding and mechanical properties of the magnesium / aluminum composite plate. Composite plates without subsequent low-temperature, short-duration, multi-pass hot rolling exhibit poor interfacial bonding and mechanical properties.

[0087] Comparative Example 3

[0088] 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 composite plate provided in Example 1, except that the 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 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 temperature 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 holding 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 of the magnesium layer and the aluminum layer during rolling, which significantly weakens the interfacial bonding performance 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 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 first hot rolling temperature of the magnesium / aluminum composite plate during the multi-pass hot rolling process is 400°C.

[0095] 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 interfacial 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 substantially consistent with the method for preparing a magnesium / aluminum composite plate provided in Example 1 in terms of operation and conditions, with the difference being that the deformation amount of the differential temperature rolling 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 oxidize 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] As shown in Table 1, the magnesium / aluminum composite plates prepared in the present invention exhibit higher tensile strength, elongation, and interfacial bonding strength than those in Comparative Examples 1-7. This indicates that the present invention effectively improves the interfacial bonding performance and overall mechanical properties of the composite plates by introducing copper foil at the interface of the magnesium / aluminum composite plates, while combining differential temperature rolling with low-temperature, short-duration, multi-pass hot rolling.

[0106] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection 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 on a magnesium plate, an aluminum plate, and a copper foil at different temperatures, wherein the magnesium plate is held at a higher temperature than the aluminum plate and the temperature difference therebetween is 110-150° C., and the copper foil is held at a lower temperature than the aluminum plate and the temperature difference therebetween 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 in multiple passes to form a magnesium / aluminum composite plate; Wherein, 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; 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; The deformation of differential temperature rolling in S2 is 65-80%; The conditions for the multi-pass 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 5-10 minutes, vacuum degree of 0.5-5 Pa, and deformation of each rolling pass of 20-30%.

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

3. The preparation process according to claim 1, 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.

4. 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 series aluminum alloy plate; and the copper foil is a pure copper metal foil or a copper alloy foil.

5. 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 according to claim 1.

6. The copper foil reinforced magnesium / aluminum composite plate according to claim 5, characterized in that: The interface bonding of the magnesium / aluminum composite plate is good, and no intermetallic compound is formed on both sides of the magnesium layer and the copper layer, or on both sides of the aluminum layer and the copper layer.

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