Magnesium / aluminum composite plate with synergistically improved strength and plasticity and preparation method thereof

Abstract

The present invention relates to the technical field of bimetallic layered composite materials, and more specifically, to a magnesium / aluminum composite plate with synergistically improved strength and plasticity and a preparation method thereof. The preparation method comprises: (1) heat-insulating a magnesium plate, an aluminum plate, and a titanium foil at different temperatures, wherein the heat-insulating temperature of the magnesium plate is higher than the heat-insulating temperature of the aluminum plate, and the temperature difference between the two is 40-70°C; the heat-insulating temperature of the titanium foil is lower than the heat-insulating temperature of the aluminum plate, and the temperature difference between the two is 20-50°C; (2) stacking the magnesium plate, aluminum plate, and titanium foil after the heat-insulating treatment in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate, and then immediately performing a large variable rolling forming to form a magnesium / aluminum composite plate. This method can not only improve the tensile strength of the magnesium / aluminum composite plate, but also improve its elongation, so that the strength and plasticity of the magnesium / aluminum composite plate are synergistically improved.

Description

Technical Field

[0001] The present invention relates to the technical field of bimetallic layered composite materials, and in particular to a magnesium / aluminum composite plate with synergistically improved strength and plasticity and a preparation method thereof. Background Art

[0002] Bimetallic composites combine the excellent mechanical properties of their constituent materials, including strength, plasticity, and wear resistance. Among the many metal composite materials, magnesium / aluminum composite plates offer broad application prospects in aerospace, automotive, and transportation, combining the excellent properties of magnesium alloys, such as low density and high specific strength, with the excellent formability and corrosion resistance of aluminum alloys. They have become a research hotspot in the light metals field both domestically and internationally. Compared to other preparation methods, rolling composites offer higher production efficiency and ease of large-scale industrial production, making them the fastest-growing and most widely used method for producing magnesium / aluminum composite plates.

[0003] Due to the difference in plastic forming ability between magnesium alloy and aluminum alloy, the deformation of magnesium plate and aluminum plate during the composite process is not coordinated, which seriously affects the interface bonding performance of the composite plate. In addition, during the hot working and subsequent heat treatment of magnesium / aluminum composite plate, the interface is very likely to form a diffusion layer with a thickness of tens to hundreds of microns. Its main components are brittle intermetallic compounds (Mg 17 Al 12 The formation of large amounts of intermetallic compounds at the interface of magnesium / aluminum composite plates has become a hot topic of research both domestically and internationally.

[0004] A few literature reports indicate that introducing metal particles or an interlayer at the interface of magnesium / aluminum composite plates can effectively reduce the amount of Mg-Al intermetallic compounds, thereby significantly improving the interfacial bonding strength. While introducing metal particles or an interlayer at the interface can improve tensile strength, it can significantly reduce the elongation of the magnesium / aluminum composite plate. Therefore, achieving magnesium / aluminum composite plates with synergistically improved strength and ductility is a pressing technical challenge.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The present invention aims to provide a magnesium / aluminum composite plate with synergistically improved strength and plasticity, and a method for preparing the same. The present invention provides a novel method for preparing a magnesium / aluminum composite plate that not only improves the tensile strength but also the elongation of the plate, thereby synergistically improving the strength and plasticity of the plate.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity, comprising:

[0009] (1) The magnesium plate, the aluminum plate, and the titanium foil are respectively subjected to insulation treatment at different temperatures, wherein the insulation temperature of the magnesium plate is higher than the insulation temperature of the aluminum plate, and the temperature difference between the two is 40-70°C; the insulation temperature of the titanium foil is lower than the insulation temperature of the aluminum plate, and the temperature difference between the two is 20-50°C;

[0010] (2) stacking the magnesium plate, the aluminum plate, and the titanium foil after the heat preservation treatment in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate, and then immediately performing a large variable rolling process to form the magnesium / aluminum composite plate.

[0011] In an optional embodiment, the magnesium plate is held at a temperature of 380-420° C. for a time of 30-50 min.

[0012] The insulation temperature of the aluminum plate is 340-380°C and the insulation time is 15-30 minutes;

[0013] The heat preservation temperature of the titanium foil is 300-340° C., and the heat preservation time is 5-10 minutes.

[0014] In an optional embodiment, the heat preservation treatment in (1) is performed in a vacuum atmosphere with a vacuum degree of 0.5-5Pa.

[0015] In an optional embodiment, the thickness ratio of the magnesium plate to the aluminum plate is (1.5-5):1, and the thickness of the titanium foil is 0.005-0.05 mm;

[0016] Preferably, the magnesium plate has a thickness of 2-4 mm.

[0017] In an optional embodiment, the magnesium plate is a Mg-Al-Zn magnesium alloy plate or a Mg-Zn-Zr magnesium alloy plate, the aluminum plate is a 5000 series aluminum alloy plate or a 6000 series aluminum alloy plate, and the titanium foil is a pure titanium foil or a titanium alloy foil.

[0018] In an optional embodiment, the rolling rate of one large variable rolling pass is 1.5-4 m / min, and the deformation of one large variable rolling pass is 60-85%.

[0019] In a second aspect, the present invention provides a magnesium / aluminum composite plate with synergistically improved strength and plasticity, wherein the magnesium / aluminum composite plate is prepared by the method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity as described in the aforementioned embodiment.

[0020] In an optional embodiment, in the magnesium / aluminum composite plate, the grain size of the magnesium layer is ≤4 μm, the basal surface texture strength is ≤9, and the texture strength of the aluminum layer is ≤4.5.

[0021] In an optional embodiment, the magnesium / aluminum composite plate has a tensile strength of 325-355 MPa, an elongation of 16.5-18%, a strength-ductility product of 5.36-6.39 GPa·%, and an interface shear strength of 105-120 MPa.

[0022] In an optional embodiment, the phase structure of the aluminum plate side of the shear section of the magnesium / aluminum composite plate is mainly Al phase, Ti phase and Mg phase, and the phase structure of the magnesium plate side is mainly Mg phase;

[0023] Preferably, no intermetallic compound is formed between the aluminum plate and the titanium foil, and between the magnesium plate and the titanium foil, and the titanium foil is continuously broken and evenly dispersed at the interface.

[0024] The present invention has the following beneficial effects: by adopting different insulation temperatures for the magnesium plate, aluminum plate and titanium foil, it helps to give full play to the plastic deformation ability of the magnesium plate, aluminum plate and titanium foil themselves, so that a significant temperature gradient is formed between the magnesium plate, aluminum plate and titanium foil, which helps to reduce the difference in deformation resistance between the magnesium plate, aluminum plate and titanium foil during the rolling process, so that the magnesium plate, aluminum plate and titanium foil obtain similar plastic deformation in a single rolling process. At the same time, the formation of Mg-Al intermetallic compounds in the traditional rolling process can be effectively suppressed by different insulation and single large deformation rolling, and the single large deformation rolling causes the titanium foil to be continuously broken near the interface and uniformly dispersed and pinned at the interface, which is beneficial to improving the interface bonding performance of the composite plate, and helps to refine the average grain size of the magnesium layer near the interface of the composite plate and weaken the texture strength of the magnesium layer and aluminum layer, achieving the beneficial effect of synergistically improving the strength and plasticity of the composite plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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.

[0026] Figure 1 The SEM image of the interface of the magnesium / aluminum composite plate prepared in Example 1 is shown;

[0027] Figure 2 The figure shows the interface XRD pattern of the magnesium / aluminum composite plate prepared in Example 1;

[0028] Figure 3EBSD image of the magnesium layer of the magnesium / aluminum composite plate prepared in Example 1;

[0029] Figure 4 EBSD image of the aluminum layer of the magnesium / aluminum composite plate prepared in Example 1;

[0030] Figure 5 Graph showing the tensile mechanical properties of the magnesium / aluminum composite plate prepared in Example 1. 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] Titanium metal has high strength, high elastic modulus, good toughness and excellent corrosion resistance, and is the most promising medium for strengthening the interface of magnesium / aluminum composite plates. However, when magnesium or aluminum plates are composited with titanium plates with a thickness of 0.2-2 mm, the tensile strength of the magnesium or aluminum plates can be effectively improved, but the elongation is greatly reduced. It can be seen that it is difficult to simultaneously improve or improve both tensile strength and elongation. The present invention provides a method for preparing magnesium / aluminum composite plates with synergistically improved strength and plasticity, which synergistically improves the tensile strength and elongation of the magnesium / aluminum composite plates.

[0033] Specifically, the preparation process is as follows:

[0034] (1) Heat treatment;

[0035] The magnesium plate, aluminum plate and titanium foil are respectively subjected to insulation treatment at different temperatures, wherein the insulation temperature of the magnesium plate is higher than the insulation temperature of the aluminum plate, and the temperature difference between the two is 40-70°C; for example, the temperature difference between the two is any value between 40°C and 70°C, such as 40°C, 50°C, 60°C and 70°C.

[0036] The insulation temperature of the titanium foil is lower than that of the aluminum plate, and the temperature difference between the two is 20-50° C. For example, it can be any value between 20° C. and 50° C., such as 20° C., 30° C., 40° C., and 50° C.

[0037] Specifically, the magnesium plate has a holding temperature of 380-420°C and a holding time of 30-50 minutes. For example, the holding temperature can be any value between 380-420°C, such as 380°C, 390°C, 400°C, 410°C, and 420°C. The holding time can be any value between 30-50 minutes, such as 30 minutes, 35 minutes, 40 minutes, 45 minutes, and 50 minutes.

[0038] The holding temperature of the aluminum plate is 340-380°C, and the holding time is 15-30 minutes. For example, the holding temperature can be any value between 340-380°C, such as 340°C, 350°C, 360°C, 370°C, and 380°C. The holding time can be any value between 15-30 minutes, such as 15 minutes, 20 minutes, 25 minutes, and 30 minutes.

[0039] The holding temperature of the titanium foil is 300-340°C, and the holding time is 5-10 minutes. For example, the holding temperature can be any value between 300-340°C, such as 300°C, 310°C, 320°C, 330°C, and 340°C. The holding time can be any value between 5-10 minutes, such as 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, and 10 minutes.

[0040] It should be noted that although the insulation temperatures of the magnesium plate, aluminum plate and titanium foil are selected from the above temperature range, it is also necessary to meet the above-mentioned requirements that the insulation temperature of the magnesium plate is higher than the insulation temperature of the aluminum plate, and the temperature difference between the two is 40-70°C, and the insulation temperature of the titanium foil is lower than the insulation temperature of the aluminum plate, and the temperature difference between the two is 20-50°C.

[0041] The embodiment of the present invention adopts different holding temperatures and holding times for the magnesium plate, aluminum plate and titanium foil, which helps to fully exert the plastic deformation ability of the magnesium plate, aluminum plate and titanium foil, so that a significant temperature gradient is formed among the magnesium plate, aluminum plate and titanium foil, which is beneficial to reducing the difference in deformation resistance among the magnesium plate, aluminum plate and titanium foil during the rolling process, so that the magnesium plate, aluminum plate and titanium foil obtain similar plastic deformation during the rolling process.

[0042] Specifically, the above heat treatment is carried out in a furnace with 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.

[0043] Vacuum heat treatment can effectively inhibit the oxidation of titanium foil during the heating process, which is beneficial to further improve the interface bonding performance of the composite plate during the rolling process, thereby obtaining a composite plate with excellent comprehensive mechanical properties.

[0044] The thickness ratio of the magnesium plate to the aluminum plate is (1.5-5):1, for example, 1.5:1, 2:1, 3:1, 4:1, 5:1, or any other value between (1.5-5):1). The thickness of the titanium foil is 0.005-0.05 mm, for example, 0.005 mm, 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, or any other value between 0.005-0.05 mm. The thickness of the magnesium plate is 2-4 mm, for example, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, or any other value between 2-4 mm.

[0045] The magnesium plate is a Mg-Al-Zn series magnesium alloy plate or a Mg-Zn-Zr series magnesium alloy plate, the aluminum plate is a 5000 series aluminum alloy plate or a 6000 series aluminum alloy plate, and the titanium foil is a pure titanium foil or a titanium alloy foil.

[0046] (2) rolling;

[0047] After the heat preservation treatment, the magnesium plate, the aluminum plate and the titanium foil are stacked in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate. The above stacking order is more conducive to improving the performance of the magnesium / aluminum composite plate.

[0048] Then, a second large variable rolling process is immediately performed to form the magnesium / aluminum composite plate. The present invention only requires one rolling process to obtain the desired magnesium / aluminum composite plate; no further rolling process is required.

[0049] The rolling rate of a single large variable rolling pass is 1.5-4 m / min, for example, 1.5 m / min, 2 m / min, 2.5 m / min, 3 m / min, 3.5 m / min, 4 m / min, or any other value between 1.5-4 m / min. The deformation of a single large variable rolling pass is 60-85%, for example, 60%, 65%, 70%, 75%, 80%, 85%, or any other value between 60-85%.

[0050] The embodiment of the present invention can effectively suppress the formation of Mg-Al intermetallic compounds in the traditional rolling process by keeping different materials at different temperatures and combining one-pass large variable rolling. In addition, one-pass large deformation rolling causes the titanium foil to be continuously broken near the interface and uniformly dispersed and pinned to the interface, which is beneficial to improving the interface bonding performance of the composite plate, and helps to refine the average grain size of the magnesium layer near the interface of the composite plate and weaken the texture strength of the magnesium layer and the aluminum layer, thereby achieving the beneficial effect of synergistically improving the strength and plasticity of the composite plate.

[0051] In a second aspect, the present invention provides a magnesium / aluminum composite plate with synergistically improved strength and plasticity, wherein the magnesium / aluminum composite plate is prepared by the method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity as described in the aforementioned embodiment.

[0052] No intermetallic compounds form between the aluminum plate and the titanium foil, nor between the magnesium plate and the titanium foil. The titanium foil undergoes continuous fragmentation and is uniformly dispersed at the interface. The shear cross-section of the magnesium / aluminum composite plate shows a phase structure primarily composed of Al, Ti, and Mg on the aluminum plate side, while the magnesium plate side is primarily composed of Mg. The magnesium layer in the magnesium / aluminum composite plate has a grain size of ≤4μm, a basal texture strength of ≤9, and a texture strength of ≤4.5 on the aluminum layer. The magnesium / aluminum composite plate exhibits a tensile strength of 325-355MPa, an elongation of 16.5-18%, a strength-ductility product of 5.36-6.39GPa·%, and an interfacial shear strength of 105-120MPa.

[0053] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0054] Example 1

[0055] An embodiment of the present invention provides a method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity, comprising:

[0056] (1) Heat treatment;

[0057] A 1 mm thick 6082 aluminum plate, a 0.01 mm thick TC4 titanium foil and a 2 mm thick ZK60 magnesium plate were subjected to insulation treatment at different temperatures and times, respectively. The insulation temperature of the ZK60 magnesium plate was 400°C and the insulation time was 40 min, the insulation temperature of the 6082 aluminum plate was 350°C and the insulation time was 25 min, and the insulation temperature of the titanium foil was 320°C and the insulation time was 7 min. The insulation treatment was carried out in a heat treatment furnace with a vacuum degree of 1 Pa.

[0058] (2) rolling;

[0059] After the insulation treatment, the magnesium plate, aluminum plate and titanium foil are stacked in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate and immediately subjected to one-pass rolling forming, wherein the one-pass rolling rate is 2m / min, the one-pass rolling deformation is 75%, and finally the required magnesium / aluminum composite plate is obtained.

[0060] The magnesium / aluminum composite plate prepared in Example 1 was tested, and the results are shown in Figures 1 to 4 ,in Figure 1 The SEM image of the interface of the magnesium / aluminum composite plate prepared in Example 1 is shown; Figure 2 The figure shows the interface XRD pattern of the magnesium / aluminum composite plate prepared in Example 1; Figure 3EBSD image of the magnesium layer of the magnesium / aluminum composite plate prepared in Example 1; Figure 4 The EBSD image of the aluminum layer of the magnesium / aluminum composite plate prepared in Example 1 is shown.

[0061] according to Figure 1 and Figure 2 It can be seen that the interface of the magnesium / aluminum composite plate is well bonded, and no obvious intermetallic compounds are formed on both sides of the aluminum plate and the titanium foil, and the magnesium plate and the titanium foil. The titanium foil is continuously broken and evenly dispersed at the interface. Figure 3 and Figure 4 It can be seen that the introduction of titanium foil can effectively refine the average grain size of the magnesium layer and the texture strength of the magnesium layer and the aluminum layer in the composite plate. The average grain size of the magnesium layer is 2.5 μm, the texture strength of the magnesium layer is 8.58, and the texture strength of the aluminum layer is 4.33.

[0062] The tensile mechanical properties of the magnesium / aluminum composite plate of Example 1 were tested. Figure 5 The magnesium / aluminum composite plate has a tensile strength of 350 MPa, an elongation of 17.5%, and a strength-ductility product of 6.125 GPa·%. Furthermore, tests show an interfacial shear strength of 118 MPa. The shear cross-section of the magnesium / aluminum composite plate on the aluminum plate side is primarily composed of Al, Ti, and Mg phases, while the magnesium plate side is primarily composed of Mg phase.

[0063] Example 2

[0064] An embodiment of the present invention provides a method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity, comprising:

[0065] (1) Heat treatment;

[0066] A 1 mm thick 6061 aluminum plate, a 0.04 mm thick pure titanium 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 420°C and the insulation time was 30 min, the insulation temperature of the 6061 aluminum plate was 350°C and the insulation time was 20 min, and the insulation temperature of the titanium foil was 310°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.

[0067] (2) rolling;

[0068] After the insulation treatment, the magnesium plate, aluminum plate and titanium foil are stacked in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate and immediately subjected to one-pass rolling forming, wherein the rolling rate of one pass is 2.5 m / min, the deformation of one pass is 70%, and finally the required magnesium / aluminum composite plate is obtained.

[0069] The magnesium / aluminum composite plate was characterized and tested for performance, and the results are as follows:

[0070] The magnesium / aluminum composite plate exhibits good interfacial bonding, with no significant intermetallic compounds forming between the aluminum plate and the titanium foil, or between the magnesium plate and the titanium foil. The titanium foil undergoes continuous fragmentation and is evenly dispersed at the interface. The introduction of titanium foil effectively refines the average grain size of the magnesium layer and the texture strengths of both the magnesium and aluminum layers in the composite plate. The average grain size of the magnesium layer is 3.5 μm, the texture strength of the magnesium layer is 8.70, and the texture strength of the aluminum layer is 4.51. The interfacial shear strength of the magnesium / aluminum composite plate is 110 MPa. The phase structure of the aluminum plate side of the shear section of the magnesium / aluminum composite plate is primarily composed of Al, Ti, and Mg phases, while the phase structure of the magnesium plate side is primarily composed of Mg phase. The magnesium / aluminum composite plate exhibits a tensile strength of 335 MPa, an elongation of 16.5%, and a strength-ductility product of 5.527 GPa·%.

[0071] Example 3

[0072] An embodiment of the present invention provides a method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity, comprising:

[0073] (1) Heat treatment;

[0074] A 1 mm thick 5052 aluminum plate, a 0.005 mm thick TC4 titanium foil and a 3 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 400°C and the insulation time was 40 min, the insulation temperature of the 5052 aluminum plate was 360°C and the insulation time was 20 min, and the insulation temperature of the titanium foil was 330°C and the insulation time was 5 min. The insulation treatment was all carried out in a heat treatment furnace with a vacuum degree of 1 Pa.

[0075] (2) rolling;

[0076] After the insulation treatment, the magnesium plate, aluminum plate and titanium foil are stacked in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate and immediately subjected to one-pass rolling forming, wherein the one-pass rolling rate is 1.5 m / min, the one-pass rolling deformation is 75%, and finally the required magnesium / aluminum composite plate is obtained.

[0077] The magnesium / aluminum composite plate exhibits good interfacial bonding, with no significant intermetallic compounds forming between the aluminum plate and the titanium foil, or between the magnesium plate and the titanium foil. The titanium foil undergoes continuous fragmentation and is evenly dispersed at the interface. The introduction of titanium foil effectively refines the average grain size of the magnesium layer and the texture strengths of both the magnesium and aluminum layers in the composite plate. The average grain size of the magnesium layer is 3.7 μm, the texture strength of the magnesium layer is 8.30, and the texture strength of the aluminum layer is 4.01. The interfacial shear strength of the magnesium / aluminum composite plate is 108 MPa. The phase structure of the aluminum plate side of the shear section of the magnesium / aluminum composite plate is primarily composed of Al, Ti, and Mg phases, while the phase structure of the magnesium plate side is primarily composed of Mg phase. The magnesium / aluminum composite plate exhibits a tensile strength of 330 MPa, an elongation of 17.0%, and a strength-ductility product of 5.61 GPa·%.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is substantially the same in terms of operation and conditions as the method for preparing the composite plate provided in Example 1, except that titanium foil is not added between the magnesium plate and the aluminum plate.

[0080] The experimental results show that the interface bonding of the composite plate without titanium foil is weak, resulting in poor mechanical properties and interface bonding strength of the composite plate.

[0081] Comparative Example 2

[0082] 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 the composite plate provided in Example 1, except that the thickness of the titanium foil is 1 mm.

[0083] The experimental results show that the 1mm thick titanium foil has weak interface bonding with the magnesium layer and the aluminum layer during the rolling process, and the titanium foil is difficult to break at the interface, which leads to a weakening of the titanium foil's interface strengthening effect, further significantly weakening the mechanical properties and interface bonding properties of the composite plate.

[0084] Comparative Example 3

[0085] 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 temperature of the magnesium plate and the aluminum plate are both 400°C.

[0086] 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 interface bonding performance and comprehensive mechanical properties of the composite plate.

[0087] Comparative Example 4

[0088] This comparative example provides a method for preparing a magnesium / aluminum composite plate. The method is substantially consistent with the method for preparing the composite plate provided in Example 1 in terms of operation and conditions, with the difference being that the deformation amount of one rolling pass is 30%.

[0089] The experimental results show that when the deformation of one rolling pass is 30%, it is difficult to achieve good bonding between the magnesium layer and the titanium layer, as well as between the aluminum layer and the titanium layer in the composite plate, resulting in extremely poor interface bonding performance and mechanical properties of the composite plate.

[0090] Comparative Example 5

[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 composite plate provided in Example 1, except that the insulation treatment of the magnesium plate, aluminum plate and titanium foil is carried out in a heat treatment furnace in an air atmosphere.

[0092] Experimental results show that titanium foil is very easy to oxidize during the insulation process, resulting in weak bonding between the layers of the composite plate, greatly reducing the interfacial bonding performance and comprehensive mechanical properties of the composite plate.

[0093] Comparative Example 6

[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 composite plate provided in Example 1, except that the magnesium plate, aluminum plate and titanium foil are stacked in the order of aluminum plate / titanium foil / magnesium plate.

[0095] The experimental results show that the two-layer magnesium / aluminum composite plate is very prone to warping during the rolling process, resulting in extremely poor interface bonding of the composite plate, greatly reducing the interface bonding performance and comprehensive mechanical properties of the composite plate.

[0096] The tensile mechanical properties and interface bonding properties of the magnesium / aluminum composite plates prepared in Comparative Examples 1-6 are shown in Table 1:

[0097] Table 1 Mechanical properties of magnesium / aluminum composite plates provided in Comparative Examples 1-6

[0098]

[0099]

[0100] 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 1-6. This indicates that the present invention, by introducing titanium foil at the interface of the magnesium / aluminum composite plate, effectively improves the interfacial bonding performance and overall mechanical properties of the composite plate, achieving a synergistic improvement in the strength and plasticity of the composite plate.

[0101] 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 method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity, characterized in that: include: (1) The magnesium plate, the aluminum plate, and the titanium foil are respectively subjected to insulation treatment at different temperatures, wherein the insulation temperature of the magnesium plate is higher than the insulation temperature of the aluminum plate, and the temperature difference between the two is 40-70°C; the insulation temperature of the titanium foil is lower than the insulation temperature of the aluminum plate, and the temperature difference between the two is 20-50°C; (2) stacking the magnesium plate, the aluminum plate and the titanium foil after the above-mentioned insulation treatment in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate, and then immediately performing a large deformation rolling process to form the magnesium / aluminum composite plate; The insulation temperature of the magnesium plate is 380-420°C and the insulation time is 30-50min; The insulation temperature of the aluminum plate is 340-380°C and the insulation time is 15-30 minutes; The holding temperature of the titanium foil is 300-340°C and the holding time is 5-10 minutes; The thickness ratio of the magnesium plate to the aluminum plate is (1.5-5):1, and the thickness of the titanium foil is 0.005-0.05 mm; The thickness of the magnesium plate is 2-4 mm; The rolling rate of the large deformation rolling in one pass is 1.5-4 m / min, and the deformation of the large deformation rolling in one pass is 60-85%.

2. The preparation method according to claim 1, characterized in that The heat preservation treatment in (1) is carried out in a vacuum atmosphere with a vacuum degree of 0.5-5Pa.

3. The preparation method according to claim 1, characterized in that The magnesium plate is a Mg-Al-Zn series magnesium alloy plate or a Mg-Zn-Zr series magnesium alloy plate, the aluminum plate is a 5000 series aluminum alloy plate or a 6000 series aluminum alloy plate, and the titanium foil is a pure titanium foil or a titanium alloy foil.

4. A magnesium / aluminum composite plate with synergistically improved strength and plasticity, characterized in that: The magnesium / aluminum composite plate is prepared by the method for preparing a magnesium / aluminum composite plate with synergistically improved strength and plasticity according to claim 1.

5. The magnesium / aluminum composite plate according to claim 4, characterized in that: In the magnesium / aluminum composite plate, the grain size of the magnesium layer is ≤4 μm, the base surface texture strength is ≤9, and the texture strength of the aluminum layer is ≤4.

5.

6. The magnesium / aluminum composite plate according to claim 4, characterized in that: The magnesium / aluminum composite plate has a tensile strength of 325-355 MPa, an elongation of 16.5-18%, a strength-ductility product of 5.36-6.39 GPa·% and an interface shear strength of 105-120 MPa.

7. The magnesium / aluminum composite plate according to claim 4, characterized in that: The phase structure of the aluminum plate side of the shear section of the magnesium / aluminum composite plate is mainly Al phase, Ti phase and Mg phase, and the phase structure of the magnesium plate side is mainly Mg phase; No intermetallic compound is formed between the aluminum plate and the titanium foil, or between the magnesium plate and the titanium foil, and the titanium foil is continuously broken and evenly dispersed at the interface.

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