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

Abstract

The invention relates to the technical field of bimetal layered composite materials, in particular to a magnesium / aluminum composite plate with synergistically improved strength and plasticity and a preparation method of the magnesium / aluminum composite plate. The preparation method comprises the steps that (1) the magnesium plate, the aluminum plate and the titanium foil are subjected to heat preservation treatment at different temperatures, the heat preservation temperature of the magnesium plate is higher than that of the aluminum plate, and the temperature difference between the magnesium plate and the aluminum plate ranges from 40 DEG C to 70 DEG C; the holding temperature of the titanium foil is lower than that of the aluminum plate, and the temperature difference between the titanium foil and the aluminum plate is 20-50 DEG C; and (2) the magnesium plate, the aluminum plate and the titanium foil which are subjected to heat preservation treatment are stacked according to the sequence of the aluminum plate / the titanium foil / the magnesium plate / the titanium foil / the aluminum plate, then one-pass large-variable rolling forming is conducted immediately, and the magnesium / aluminum composite plate is formed. The method not only can improve the tensile strength of the magnesium / aluminum composite plate, but also can improve the elongation of the magnesium / aluminum composite plate, 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 composite materials can combine the excellent mechanical properties of their constituent materials, including strength, plasticity and wear resistance. Among many metal composite materials, magnesium / aluminum composite plates have broad application prospects in aerospace, automobile, transportation and other 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. They have become a research hotspot in the field of light metals at home and abroad. Compared with other preparation methods, rolling composite has higher production efficiency and is easy to achieve large-scale industrial production. It is currently 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 is not coordinated during the composite process, 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, the main component of which is brittle metal compound (Mg 17 Al 12 During the loading process of the composite plate, these intermetallic compounds can easily become crack sources, 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] A few literatures have reported that by introducing metal particles or an intermediate layer at the interface of magnesium / aluminum composite plates, the amount of Mg-Al intermetallic compounds can be effectively reduced, thereby greatly improving the bonding strength of the interface. Although the introduction of metal particles or an intermediate layer at the interface can improve its tensile strength, it will cause a significant decrease in the elongation of the magnesium / aluminum composite plate. Therefore, how to obtain a magnesium / aluminum composite plate with synergistically improved strength and plasticity is a technical problem that needs to be solved urgently.

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

[0006] The object of the present invention is to provide a magnesium / aluminum composite plate with synergistically improved strength and plasticity and a preparation method thereof. The embodiment of the present invention provides a new preparation method of a magnesium / aluminum composite plate, which 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.

[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 insulation 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 insulation temperature of the magnesium plate is 380-420° C. and the insulation time is 30-50 min;

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

[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 is 1.5-4 m / min, and the deformation of one large variable rolling 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 base 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 both sides of 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 magnesium plate, aluminum plate and titanium foil, it is helpful to give full play to the plastic deformation ability of magnesium plate, aluminum plate and titanium foil, so that a significant temperature gradient is formed between magnesium plate, aluminum plate and titanium foil, which is helpful to reduce the difference in deformation resistance between magnesium plate, aluminum plate and titanium foil during rolling, so that magnesium plate, aluminum plate and titanium foil obtain similar plastic deformation in one rolling process. At the same time, different insulation and one large deformation rolling can effectively inhibit the formation of Mg-Al intermetallic compounds in the traditional rolling process, and one large deformation rolling causes the titanium foil to be continuously broken near the interface and evenly dispersed and pinned to the interface, which is helpful to improve 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, so as to achieve the beneficial effect of synergistic improvement of 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 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.

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

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

[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 The figure shows the tensile mechanical properties of the magnesium / aluminum composite plate prepared in Example 1. 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] 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 improve or improve both tensile strength and elongation at the same time, and the present invention provides a method for preparing a magnesium / aluminum composite plate with synergistic improvement in strength and plasticity, which synergistically improves the tensile strength and elongation of the magnesium / aluminum composite plate.

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

[0034] (1) Heat treatment;

[0035] 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; for example, the temperature difference between the two is any value between 40°C-70°C, such as 40°C, 50°C, 60°C and 70°C.

[0036] The heat preservation 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 is any value between 20° C. and 50° C., such as 20° C., 30° C., 40° C., and 50° C.

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

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

[0039] The heat preservation temperature of the titanium foil is 300-340°C, and the heat preservation time is 5-10 minutes. For example, the heat preservation temperature is 300°C, 310°C, 320°C, 330°C, 340°C, and any other value between 300-340°C. The heat preservation time is 5-10 minutes, and any other value between 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, and any other value between 5 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 insulation temperatures and insulation times for the magnesium plate, aluminum plate and titanium foil, which helps to give full play to the plastic deformation ability of the magnesium plate, aluminum plate and titanium foil, so that a significant temperature gradient is formed between the magnesium plate, aluminum plate and titanium foil, which is beneficial to reducing 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 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 0.5-5Pa, for example, any value between 0.5-5Pa, such as 0.5Pa, 1Pa, 2Pa, 3Pa, 4Pa and 5Pa.

[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, any value between (1.5-5):1 such as 1.5:1, 2:1, 3:1, 4:1 and 5:1. The thickness of the titanium foil is 0.005-0.05mm; for example, the titanium foil is any value between 0.005mm, 0.01mm, 0.02mm, 0.03mm, 0.04mm and 0.05mm. The thickness of the magnesium plate is 2-4mm, for example, any value between 2-4mm such as 2mm, 2.5mm, 3mm, 3.5mm and 4mm.

[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] The magnesium plate, the aluminum plate and the titanium foil after the insulation treatment are stacked in the order of aluminum plate / titanium foil / magnesium plate / titanium foil / aluminum plate. The stacking order is more conducive to improving the performance of the magnesium / aluminum composite plate.

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

[0049] The rolling rate of a large variable rolling is 1.5-4m / min, for example, 1.5m / min, 2m / min, 2.5m / min, 3m / min, 3.5m / min, 4m / min, etc., any value between 1.5-4m / min. The deformation of a large variable rolling is 60-85%, for example, 60%, 65%, 70%, 75%, 80%, 85%, etc., any 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 a single large variable rolling. The single large deformation rolling causes the titanium foil to be continuously broken near the interface and evenly 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 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 are formed between the aluminum plate and the titanium foil, and between the magnesium plate and the titanium foil. The titanium foil is continuously broken and evenly dispersed at the interface. The physical 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 physical structure of the magnesium plate side is mainly Mg phase; the grain size of the magnesium layer in the magnesium / aluminum composite plate is ≤4μm, the base surface texture strength is ≤9, and the texture strength of the aluminum layer is ≤4.5. The tensile strength of the magnesium / aluminum composite plate is 325-355MPa, the elongation is 16.5-18%, the strength-ductility product is 5.36-6.39GPa·%; the interface shear strength is 105-120MPa.

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

[0054] Example 1

[0055] The 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] 1mm thick 6082 aluminum plate, 0.01mm thick TC4 titanium foil and 2mm thick ZK60 magnesium plate were subjected to insulation treatment at different temperatures and times, wherein the insulation temperature of the ZK60 magnesium plate was 400℃, the insulation time was 40min, the insulation temperature of the 6082 aluminum plate was 350℃, the insulation time was 25min, the insulation temperature of the titanium foil was 320℃, the insulation time was 7min, and the insulation treatment was carried out in a heat treatment furnace with a vacuum degree of 1Pa.

[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 2 m / min, the one-pass rolling deformation is 75%, and finally the desired 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 interface SEM image of the magnesium / aluminum composite plate prepared in Example 1 is shown; Figure 2 The interface XRD pattern of the magnesium / aluminum composite plate prepared in Example 1 is shown; 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, no obvious intermetallic compounds are formed between the aluminum plate and the titanium foil, and between 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 are tested, see Figure 5 Among them, the tensile strength of the magnesium / aluminum composite plate is 350MPa, the elongation is 17.5%, and the strength-ductility product is 6.125GPa·%. In addition, the test shows that the interface shear strength of the magnesium / aluminum composite plate is 118MPa. 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.

[0063] Example 2

[0064] The 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] The 1 mm thick 6061 aluminum plate, the 0.04 mm thick pure titanium foil and the 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 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 one-pass rolling rate is 2.5 m / min, the one-pass rolling deformation is 70%, and finally the desired 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 interface of the magnesium / aluminum composite plate is well bonded. 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. 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 3.5μm, the texture strength of the magnesium layer is 8.70, and the texture strength of the aluminum layer is 4.51. The interface shear strength of the magnesium / aluminum composite plate is 110MPa. 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. The tensile strength of the magnesium / aluminum composite plate is 335MPa, the elongation is 16.5%, and the strength-ductility product is 5.527GPa·%.

[0071] Example 3

[0072] The 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] The 1 mm thick 5052 aluminum plate, the 0.005 mm thick TC4 titanium foil and the 3 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 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 treatments were 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 desired magnesium / aluminum composite plate is obtained.

[0077] The interface of the magnesium / aluminum composite plate is well bonded. 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. 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 3.7μm, the texture strength of the magnesium layer is 8.30, and the texture strength of the aluminum layer is 4.01. The interface shear strength of the magnesium / aluminum composite plate is 108MPa. 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. The tensile strength of the magnesium / aluminum composite plate is 330MPa, the elongation is 17.0%, and the strength-ductility product is 5.61GPa·%.

[0078] Comparative Example 1

[0079] 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 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 adding 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 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 thickness of the titanium foil is 1 mm.

[0083] The experimental results show that the 1 mm 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 the weakening of the effect of titanium foil strengthening the interface, 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 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 insulation temperatures 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 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 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 basically consistent with the method for preparing a composite plate provided in Example 1 in terms of operation and conditions, except 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 for the magnesium layer and the titanium layer, as well as the aluminum layer and the titanium layer in the composite plate to achieve good bonding, 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 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 insulation treatment of the magnesium plate, aluminum plate and titanium foil is carried out in a heat treatment furnace in an air atmosphere.

[0092] The 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 interface 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 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 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 by comparative examples 1-6

[0098]

[0099]

[0100] According to Table 1, compared with Comparative Examples 1-6, 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 titanium foil at the interface of the magnesium / aluminum composite plate, thereby achieving a synergistic improvement in the strength and plasticity of the composite plate.

[0101] 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 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 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.

2. The preparation method according to claim 1, characterized in that: 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 15-30min; The heat preservation temperature of the titanium foil is 300-340° C., and the heat preservation time is 5-10 minutes.

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

4. The preparation method according to claim 1, characterized in that: 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; Preferably, the magnesium plate has a thickness of 2-4 mm.

5. 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.

6. The preparation method according to claim 1, characterized in that: The rolling rate of the large deformation rolling in one pass is 1.5-4m / min, and the deformation of the large deformation rolling in one pass is 60-85%.

7. 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 as described in claim 1.

8. The magnesium / aluminum composite plate according to claim 7, 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.

9. The magnesium / aluminum composite plate according to claim 7, 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.

10. The magnesium / aluminum composite plate according to claim 7, 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; Preferably, no intermetallic compound is formed between the aluminum plate and the titanium foil, and between the magnesium plate and both sides of the titanium foil, and the titanium foil is continuously broken and evenly dispersed at the interface.

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