Zinc interlayer reinforced magnesium-aluminum composite board and preparation method thereof

Abstract

The invention relates to the technical field of magnesium-aluminum layered composite materials, in particular to a zinc interlayer reinforced magnesium-aluminum composite plate and a preparation method thereof. The preparation method comprises the following steps: respectively carrying out heat preservation treatment on a magnesium plate, an aluminum plate and a zinc foil at different temperatures, then stacking the magnesium plate, the aluminum plate and the zinc foil which are subjected to heat preservation treatment according to an aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate sequence, and then immediately carrying out single-pass rolling to form a magnesium-aluminum composite plate blank; and then, the magnesium-aluminum composite plate blank is subjected to multi-pass hot rolling. According to the preparation method provided by the embodiment of the invention, the interface bonding performance and the comprehensive mechanical performance of the magnesium-aluminum composite board are effectively improved, the interface bonding strength of the magnesium-aluminum composite board is 75-90 MPa, the tensile strength is 320-340 MPa, and the ductility is 15-18%.

Description

Technical Field

[0001] The invention relates to the technical field of magnesium-aluminum layered composite materials, and in particular to a magnesium-aluminum composite plate reinforced with a zinc intermediate layer and a preparation method thereof. Background Art

[0002] Magnesium and magnesium alloys are widely used in the automotive, aerospace and consumer electronics industries due to their low density, high specific strength, excellent damping performance and electromagnetic shielding performance. However, their poor formability, poor corrosion resistance and low absolute strength seriously hinder their widespread application. Magnesium-aluminum composite panels have broad application prospects in the fields of aerospace, automobiles, transportation, etc. 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] There are many methods for preparing magnesium-aluminum composite plates in the prior art, among which rolling composite has the advantages of high production efficiency and easy large-scale industrial production. Therefore, it has become the fastest growing and most widely used method for producing magnesium-aluminum composite plates.

[0004] However, there are many problems in rolling the magnesium-aluminum composite plate. For example, during the hot working and subsequent heat treatment process, the interface of the magnesium-aluminum composite plate is prone to form a diffusion layer with a thickness of tens to hundreds of microns, the main component of which is the intermetallic compound Mg. 17 Al 12 The main metals are Mg2Al3 and Mg2Al3, however, these intermetallic compounds are hard and brittle phases, and they can easily become crack sources during the loading process of the composite plate, greatly weakening the strength and plasticity of the composite plate. Therefore, how to avoid the generation of a large number of intermetallic compounds at the interface of the medium magnesium aluminum composite plate has become a hot topic of research at home and abroad.

[0005] The researchers improved the interface structure of the magnesium-aluminum composite plate by adding metal powder to the interface to reduce the number of intermetallic compounds and thus improve the interface bonding strength of the composite plate. Compared with powder, the metal interlayer can be more evenly distributed in the interface of the composite plate, and is expected to fully play the role of improving the interface bonding strength. However, what kind of metal interlayer to use and how to operate it so that the metal interlayer can improve the performance of the magnesium-aluminum composite plate are technical difficulties that researchers need to solve.

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

[0007] The object of the present invention is to provide a magnesium-aluminum composite plate reinforced with a zinc intermediate layer and a preparation method thereof. The embodiment of the present invention provides a new preparation method that can improve the above-mentioned problems of the prior art.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a method for preparing a magnesium-aluminum composite plate reinforced with a zinc intermediate layer, comprising:

[0010] Step 1: respectively subjecting the magnesium plate, the aluminum plate and the zinc foil to insulation treatment at different temperatures, wherein the temperature of the aluminum plate is lower than that of the magnesium plate, and the temperature difference between the two is 80-100°C, and the temperature of the magnesium plate is higher than that of the zinc foil, and the temperature difference between the two is 30-60°C;

[0011] Step 2: stacking the magnesium plate, the aluminum plate and the zinc foil after the insulation treatment in the order of aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate, and then immediately performing single-pass rolling to form a magnesium-aluminum composite slab;

[0012] Step 3: hot rolling the magnesium-aluminum composite plate blank for multiple passes to form the magnesium-aluminum composite plate.

[0013] In an optional embodiment, the insulation temperature of the magnesium plate is 300-380° C., and the insulation time is 24-45 min;

[0014] The insulation temperature of the aluminum plate is 250-300°C, and the insulation time is 20-30min;

[0015] The insulation temperature of the zinc foil is 290-350° C., and the insulation time is 10-15 minutes.

[0016] In an optional embodiment, the heat preservation and heat treatment in step 1 is performed in an air atmosphere.

[0017] In an optional embodiment, in step 1, the thickness ratio of the aluminum plate to the magnesium plate is (1:2)-(2:1), and the thickness of the zinc foil is 0.01-0.2 mm;

[0018] Preferably, the magnesium plate has a thickness of 1-2 mm.

[0019] In an optional embodiment, the deformation amount of a single rolling pass in step 2 is 45-60%.

[0020] In an optional embodiment, the number of rolling passes in the multi-pass hot rolling in step 3 is at least 2;

[0021] The conditions for each rolling are: temperature of 230-280°C, time of 10-15min, deformation of each rolling pass of 40-50%, and heat preservation of each pass is carried out in air atmosphere.

[0022] In an optional embodiment, the aluminum plate in step 1 is a 5000 series or 6000 series aluminum alloy plate, the magnesium plate is a Mg-Al-Zn series or Mg-Zn-Zr series magnesium alloy plate, and the zinc foil is a pure zinc foil or a zinc alloy foil.

[0023] In a second aspect, the present invention provides a zinc intermediate layer reinforced magnesium-aluminum composite plate, which is prepared by the method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate described in any one of the aforementioned embodiments.

[0024] In an optional embodiment, the interface bonding of the magnesium-aluminum composite plate is good, no intermetallic compound is formed between the aluminum layer and the zinc layer, a diffusion layer mainly composed of MgZn2 phase is formed between the magnesium layer and the zinc layer, and the thickness of the diffusion layer is ≤2 μm;

[0025] Preferably, the average grain size of the magnesium layer in the magnesium-aluminum composite plate is ≤3.5 μm, the basal texture strength of the magnesium layer is ≤9.2, and the texture strength of the aluminum layer is ≤4.2.

[0026] In an optional embodiment, the magnesium-aluminum composite plate has an interface bonding strength of 75-90 MPa, a tensile strength of 320-340 MPa, and an elongation of 15-18%.

[0027] The present invention has the following beneficial effects: The embodiment of the present invention helps to give full play to the plastic deformation ability of the magnesium plate, aluminum plate and zinc foil by performing insulation treatment at different temperatures on the magnesium plate, aluminum plate and zinc foil, so that a significant temperature gradient is formed between the magnesium plate, aluminum plate and zinc foil, which is beneficial to reduce the difference in deformation resistance between the magnesium plate, aluminum plate and zinc foil during rolling, so that the magnesium plate, aluminum plate and zinc foil obtain similar plastic deformation amounts during a single-pass rolling process. The introduction of ultra-thin zinc foil can further realize the rolling composite of the magnesium-aluminum composite plate at a lower temperature, coordinate the deformation of the magnesium plate and the aluminum plate, refine the average grain size of the magnesium layer, weaken the texture strength of the composite plate, and improve the plastic forming ability of the magnesium-aluminum composite plate. At the same time, single-pass rolling combined with multi-pass rolling is conducive to achieving good metallurgical bonding at the interface between the magnesium layer and the zinc layer and the aluminum layer and the zinc layer, and an extremely thin element interdiffusion layer is formed near the interface between the magnesium layer and the zinc layer, which significantly improves the interface bonding performance of the magnesium-aluminum composite plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] 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.

[0029] Figure 1 The interface SEM image of the magnesium-aluminum composite plate prepared in Example 1 is shown;

[0030] Figure 2 The interface EBSD image of the magnesium-aluminum composite plate prepared in Example 1 is shown;

[0031] Figure 3 The figure shows the tensile mechanical properties of the magnesium-aluminum composite plate prepared in Example 1. DETAILED DESCRIPTION

[0032] 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.

[0033] The embodiment of the present invention provides a method for preparing a magnesium-aluminum composite plate reinforced with a zinc intermediate layer, comprising:

[0034] Step 1, heat preservation treatment;

[0035] The magnesium plate, aluminum plate and zinc foil were subjected to insulation treatment at different temperatures. The melting point of metal zinc is low (about 420°C), and using zinc as the middle layer of the magnesium / aluminum composite plate is conducive to the good bonding of the composite plate at a lower temperature. In addition, zinc and magnesium both have a close-packed hexagonal crystal structure, which is conducive to coordinating the deformation of magnesium and aluminum during deformation, and is expected to improve the plastic forming ability of the magnesium / aluminum composite plate.

[0036] The temperature of the aluminum plate is lower than that of the magnesium plate, and the temperature difference between the two is 80-100°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, etc., any value between 80-100°C. The temperature of the magnesium plate is higher than that of the zinc foil, and the temperature difference between the two is 30-60°C; such as 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, etc., any value between 30-60°C.

[0037] The insulation temperature of the magnesium plate is 300-380°C, and the insulation time is 24-45 minutes; for example, the temperature is 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, and any other value between 300-380°C. The time is 24 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, and any other value between 24-45 minutes.

[0038] The insulation temperature of the aluminum plate is 250-300°C, and the insulation time is 20-30min; for example, the temperature is any value between 250-300°C, such as 250°C, 260°C, 270°C, 280°C, 290°C and 300°C. The insulation time is any value between 20-30min, such as 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min and 30min.

[0039] The insulation temperature of the zinc foil is 290-350°C, and the insulation time is 10-15 minutes. For example, it is any value between 290°C, 300°C, 310°C, 320°C, 330°C, 340°C and 350°C. The insulation time is any value between 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes and 15 minutes.

[0040] The embodiment of the present invention limits the insulation temperature of the magnesium plate, the aluminum plate and the zinc foil and restricts the temperature difference, which helps to give full play to the plastic deformation capacity of the magnesium plate, the aluminum plate and the zinc foil, so that an obvious temperature gradient is formed between the magnesium plate, the aluminum plate and the zinc foil, which is beneficial to reducing the difference in deformation resistance between the magnesium plate, the aluminum plate and the zinc foil during the rolling process, so that the magnesium plate, the aluminum plate and the zinc foil obtain similar plastic deformation during the rolling process, which is beneficial to improving the performance of the magnesium-aluminum composite plate.

[0041] Furthermore, the above-mentioned heat preservation treatment is carried out in an air atmosphere. In the embodiment of the present invention, the air atmosphere is adopted, and the zinc foil can still maintain good anti-oxidation, which is beneficial to the interface bonding of the composite plate during the rolling process, thereby improving the comprehensive mechanical properties of the composite plate.

[0042] In step 1, the thickness ratio of the aluminum plate to the magnesium plate is (1:2)-(2:1), such as 1:2, 1:1, 2:1, etc., and any value between (1:2)-(2:1). The thickness of the magnesium plate is 1-2 mm, such as 1 mm, 1.5 mm, and 2 mm, and any value between 1-2 mm.

[0043] The thickness of the zinc foil is 0.01-0.2 mm. For example, it is any value between 0.01-0.2 mm, such as 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm and 0.2 mm. Selecting ultra-thin zinc foil can further realize the rolling and compounding of the magnesium-aluminum composite plate at a lower temperature, coordinate the deformation of the magnesium plate and the aluminum plate, refine the average grain size of the magnesium layer, weaken the texture strength of the composite plate, and improve the plastic forming ability of the magnesium-aluminum composite plate.

[0044] The aluminum plate is a 5000 series or 6000 series aluminum alloy plate, the magnesium plate is a Mg-Al-Zn series or Mg-Zn-Zr series magnesium alloy plate, and the zinc foil is a pure zinc foil or a zinc alloy foil.

[0045] Step 2, single pass rolling;

[0046] The magnesium plate, the aluminum plate and the zinc foil after the insulation treatment are stacked in the order of aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate, and then single-pass rolling is immediately performed to form a magnesium-aluminum composite slab; wherein the deformation amount of the single-pass rolling is 45-60%, for example, any value between 45%, 50%, 55% and 60%, etc.

[0047] Step 3, multi-pass rolling;

[0048] The magnesium-aluminum composite plate blank is subjected to multiple hot rolling to form the magnesium-aluminum composite plate. The multiple hot rolling in the embodiment of the present invention is conducive to achieving good metallurgical bonding at the interface between the magnesium layer and the zinc layer and the aluminum layer and the zinc layer, and an extremely thin element interdiffusion layer is formed near the interface between the magnesium layer and the zinc layer, which significantly improves the interface bonding performance of the magnesium-aluminum composite plate.

[0049] Specifically, the number of rolling passes in the multi-pass hot rolling is at least 2; the conditions for each rolling are: the temperature is 230-280°C, the time is 10-15min, and the deformation of each rolling pass is 40-50%. Specifically, the temperature is any value between 230-280°C, such as 230°C, 240°C, 250°C, 260°C, 270°C and 280°C. The time is any value between 10-15min, such as 10min, 11min, 12min, 13min, 14min and 15min. The deformation is any value between 40% and 50%, such as 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% and 50%.

[0050] Each insulation pass is carried out in an air atmosphere.

[0051] In a second aspect, the present invention provides a zinc intermediate layer reinforced magnesium-aluminum composite plate, which is prepared by the method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate described in any one of the aforementioned embodiments.

[0052] Specifically, the interface bonding of the magnesium-aluminum composite plate is good, no intermetallic compound is formed between the aluminum layer and the zinc layer, a diffusion layer mainly composed of MgZn2 phase is formed between the magnesium layer and the zinc layer, and the thickness of the diffusion layer is ≤2μm; the average grain size of the magnesium layer in the magnesium-aluminum composite plate is ≤3.5μm, the base surface texture strength of the magnesium layer is ≤9.2, and the texture strength of the aluminum layer is ≤4.2. The interface bonding strength of the magnesium-aluminum composite plate is 75-90MPa, the tensile strength is 320-340MPa, and the elongation is 15-18%.

[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 reinforced with a zinc intermediate layer, comprising:

[0056] S1, thermal insulation treatment;

[0057] 1mm thick 6061 aluminum plate, 0.05mm thick zinc foil and 2mm 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 350℃, the insulation time was 30min, the insulation temperature of the 6061 aluminum plate was 260℃, the insulation time was 25min, the insulation temperature of the zinc foil was 300℃, the insulation time was 10min, and the insulation treatment was all carried out in an air heat treatment furnace.

[0058] S2, single pass rolling;

[0059] After the heat preservation treatment, the magnesium plate, aluminum plate and zinc foil are stacked in the order of aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate and then immediately subjected to single-pass rolling forming, wherein the single-pass rolling deformation is 60%, forming a magnesium-aluminum composite slab.

[0060] S3, multi-pass rolling;

[0061] Subsequently, the prepared magnesium-aluminum composite slab was rolled in two passes. The first rolling temperature was 250°C, the holding time was 10 minutes, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 40%; the second rolling temperature was 240°C, the holding time was 10 minutes, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 50%, and finally a magnesium-aluminum composite plate reinforced with a zinc intermediate layer was obtained.

[0062] Characterization

[0063] The magnesium-aluminum composite plate prepared in Example 1 was characterized. The results are shown in Figures 1 to 3 ,in Figure 1 The interface SEM image of the magnesium-aluminum composite plate is shown; Figure 2 Represents the interface EBSD map of the magnesium-aluminum composite plate; Figure 3 Graph showing the tensile mechanical properties of magnesium-aluminum composite plates.

[0064] like Figure 1-Figure 3 As shown, the interface of the magnesium-aluminum composite plate is well bonded, the thickness of the zinc layer is about 7μm, the aluminum layer and the zinc layer do not form intermetallic compounds, and a diffusion layer mainly composed of MgZn2 phase is formed at the interface between the magnesium layer and the zinc layer. The diffusion layer thickness is about 1μm, the average grain size of the magnesium layer is 3μm, the texture strength of the magnesium layer is 9.11, and the texture strength of the aluminum layer is 4.11. The tensile strength of the magnesium-aluminum composite plate is 330MPa, the elongation is 16%, and the interface bonding strength is 85MPa.

[0065] Example 2

[0066] This embodiment provides a method for preparing a magnesium-aluminum composite plate reinforced with a zinc intermediate layer, comprising:

[0067] S1, thermal insulation treatment;

[0068] 1mm thick 6082 aluminum plate, 0.1mm thick zinc foil and 2mm thick AZ31 magnesium plate were subjected to insulation treatment at different temperatures and for different times, wherein the insulation temperature of AZ31 magnesium plate was 380℃, the insulation time was 27min, the insulation temperature of 6082 aluminum plate was 290℃, the insulation time was 30min, the insulation temperature of zinc foil was 320℃, the insulation time was 10min, and the insulation treatment was all carried out in an air heat treatment furnace.

[0069] S2, single pass rolling;

[0070] After the heat preservation treatment, the magnesium plate, aluminum plate and zinc foil are stacked in the order of aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate and then immediately subjected to single-pass rolling forming, wherein the single-pass rolling deformation amount is 45%, to form a magnesium-aluminum composite slab.

[0071] S3, multi-pass rolling;

[0072] Subsequently, the prepared magnesium-aluminum composite slab was rolled in three passes, wherein the first rolling temperature was 250°C, the holding time was 10 min, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 40%; the second rolling temperature was 240°C, the holding time was 15 min, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 40%; the third rolling temperature was 235°C, the holding time was 12 min, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 45%, and finally a zinc intermediate layer reinforced magnesium-aluminum composite plate was obtained.

[0073] Characterization

[0074] The magnesium-aluminum composite plate has good interface bonding, the zinc layer thickness is about 11μm, the aluminum layer and the zinc layer do not form intermetallic compounds, and the magnesium layer and the zinc layer interface form a diffusion layer mainly composed of MgZn2 phase, the diffusion layer thickness is about 1.5μm, the average grain size of the magnesium layer is 2.7μm, the texture strength of the magnesium layer is 9.02, and the texture strength of the aluminum layer is 4.01. The tensile strength of the magnesium-aluminum composite plate is 335MPa, the elongation is 17%, and the interface bonding strength is 90MPa.

[0075] Example 3

[0076] This embodiment provides a method for preparing a magnesium-aluminum composite plate reinforced with a zinc intermediate layer, comprising:

[0077] S1, thermal insulation treatment;

[0078] 1mm thick 5052 aluminum plate, 0.1mm thick zinc foil and 1mm thick ZK60 magnesium plate were subjected to insulation treatment at different temperatures and for different times, wherein the insulation temperature of the ZK60 magnesium plate was 340°C and the insulation time was 40min, the insulation temperature of the 5052 aluminum plate was 260°C and the insulation time was 30min, and the insulation temperature of the zinc foil was 300°C and the insulation time was 12min. The insulation treatments were all carried out in an air heat treatment furnace.

[0079] S2, single pass rolling;

[0080] After the heat preservation treatment, the magnesium plate, aluminum plate and zinc foil are stacked in the order of aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate and then immediately subjected to single-pass rolling forming, wherein the single-pass rolling deformation is 55%, to form a magnesium-aluminum composite slab.

[0081] S3, multi-pass rolling;

[0082] Subsequently, the prepared magnesium-aluminum composite slab was rolled in two passes. The first rolling temperature was 235°C, the holding time was 15 minutes, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 45%; the second rolling temperature was 230°C, the holding time was 12 minutes, the holding treatment was carried out in an air atmosphere, and the rolling deformation was 50%, and finally a zinc intermediate layer reinforced magnesium-aluminum composite plate was obtained.

[0083] Characterization

[0084] The magnesium-aluminum composite plate has good interface bonding, the zinc layer thickness is about 15μm, the aluminum layer and the zinc layer do not form intermetallic compounds, and the magnesium layer and the zinc layer interface form a diffusion layer mainly composed of MgZn2 phase, the diffusion layer thickness is about 0.5μm, the average grain size of the magnesium layer is 3.3μm, the texture strength of the magnesium layer is 9.14, and the texture strength of the aluminum layer is 4.12. The tensile strength of the magnesium-aluminum composite plate is 328MPa, the elongation is 16%, and the interface bonding strength is 80MPa.

[0085] Comparative Example 1

[0086] This comparative example provides a method for preparing a magnesium-aluminum composite plate, comprising:

[0087] 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 zinc foil is not added between the magnesium plate and the aluminum plate.

[0088] The experimental results show that the absence of low-melting-point zinc foil makes it difficult for the magnesium-aluminum composite plate to achieve good bonding at a lower rolling temperature, resulting in poor interface bonding and mechanical properties of the composite plate.

[0089] Comparative Example 2

[0090] This comparative example provides a method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate, comprising:

[0091] 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 insulation temperature of the magnesium plate and the aluminum plate are both 350°C.

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

[0093] Comparative Example 3

[0094] This comparative example provides a method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate, comprising:

[0095] 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 no subsequent multiple rolling passes are performed.

[0096] The experimental results show that low-temperature, short-time multi-pass rolling is beneficial to the grain refinement of the magnesium layer and the aluminum layer in the composite plate, and significantly improves the interface bonding performance and mechanical properties of the composite plate. The interface bonding performance and mechanical properties of the composite plate without subsequent low-temperature, short-time multi-pass rolling are poor.

[0097] Comparative Example 4

[0098] This comparative example provides a method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate, comprising:

[0099] 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, the aluminum plate and the zinc foil are stacked in the order of aluminum plate / zinc foil / magnesium plate.

[0100] 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.

[0101] Comparative Example 5

[0102] This comparative example provides a method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate, comprising:

[0103] 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 first rolling temperature of the magnesium-aluminum composite plate during the multi-pass rolling process is 400°C.

[0104] The experimental results show that when the composite plate is rolled at 400℃ in the first pass after multiple rolling, a diffusion layer with a thickness of more than tens of microns is easily formed at the interface. These diffusion layers are mainly intermetallic compounds of Mg-Zn and Al-Zn. These hard and brittle intermetallic compounds are significantly broken during the subsequent second rolling process, greatly weakening the interface bonding performance and mechanical properties of the composite plate.

[0105] Comparative Example 6

[0106] This comparative example provides a method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate, comprising:

[0107] 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 deformation amount of a single rolling pass is 30%.

[0108] The experimental results show that when the deformation of a single rolling pass is 30%, it is difficult for the magnesium layer and the zinc layer, as well as the aluminum layer and the zinc layer in the composite plate to achieve good bonding, resulting in extremely poor interface bonding performance and mechanical properties of the composite plate.

[0109] Comparative Example 7

[0110] This comparative example provides a method for preparing a zinc intermediate layer reinforced magnesium-aluminum composite plate, comprising:

[0111] 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 aluminum plate and the zinc foil are both 260°C.

[0112] The experimental results show that the plastic deformation capabilities of aluminum plates and zinc foils 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 aluminum layer and the zinc layer during rolling, which in turn significantly weakens the interface bonding performance and comprehensive mechanical properties of the composite plate.

[0113] The tensile mechanical properties and interface bonding properties of the composite plates prepared in Comparative Examples 1-7 are shown in Table 1.

[0114] Table 1 Mechanical properties test of magnesium-aluminum composite plates of comparative examples 1-7

[0115]

[0116] According to Table 1, compared with Comparative Examples 1-7, the magnesium-aluminum composite plate prepared in the embodiment of the present invention has higher tensile strength, elongation and interface bonding strength, which indicates that the embodiment of the present invention effectively improves the interface bonding performance and comprehensive mechanical properties of the composite plate by introducing zinc foil at the interface of the magnesium-aluminum composite plate and combining single-pass rolling and multi-pass hot rolling.

[0117] 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 reinforced with a zinc intermediate layer, characterized in that: include: Step 1: respectively subjecting the magnesium plate, the aluminum plate and the zinc foil to insulation treatment at different temperatures, wherein the temperature of the aluminum plate is lower than that of the magnesium plate, and the temperature difference between the two is 80-100°C, and the temperature of the magnesium plate is higher than that of the zinc foil, and the temperature difference between the two is 30-60°C; Step 2: stacking the magnesium plate, the aluminum plate and the zinc foil after the insulation treatment in the order of aluminum plate / zinc foil / magnesium plate / zinc foil / aluminum plate, and then immediately performing single-pass rolling to form a magnesium-aluminum composite slab; Step 3: hot rolling the magnesium-aluminum composite plate blank for multiple passes 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 300-380°C, and the insulation time is 24-45min; The insulation temperature of the aluminum plate is 250-300°C, and the insulation time is 20-30min; The insulation temperature of the zinc foil is 290-350° C., and the insulation time is 10-15 minutes.

3. The preparation method according to claim 1 or 2, characterized in that: The heat preservation heat treatment in step 1 is all carried out in an air atmosphere.

4. The preparation method according to claim 1, characterized in that: In step 1, the thickness ratio of the aluminum plate to the magnesium plate is (1:2)-(2:1), and the thickness of the zinc foil is 0.01-0.2 mm; Preferably, the magnesium plate has a thickness of 1-2 mm.

5. The preparation method according to claim 1, characterized in that: The deformation amount of a single rolling pass in step 2 is 45-60%.

6. The preparation method according to claim 1, characterized in that: The number of rolling passes in the multi-pass hot rolling in step 3 is at least 2; The conditions for each rolling are: temperature of 230-280°C, time of 10-15min, deformation of each rolling pass of 40-50%, and heat preservation of each pass is carried out in air atmosphere.

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

8. A magnesium-aluminum composite plate reinforced with a zinc intermediate layer, characterized in that: The magnesium-aluminum composite plate is prepared by the method for preparing a magnesium-aluminum composite plate reinforced with a zinc intermediate layer as described in any one of claims 1 to 7.

9. The magnesium-aluminum composite plate reinforced with a zinc intermediate layer according to claim 8, characterized in that: The magnesium-aluminum composite plate has good interface bonding, no intermetallic compound is formed between the aluminum layer and the zinc layer, and a diffusion layer mainly composed of MgZn2 phase is formed between the magnesium layer and the zinc layer, and the thickness of the diffusion layer is ≤2 μm; Preferably, in the magnesium-aluminum composite plate, the average grain size of the magnesium layer is ≤3.5 μm, the basal surface texture strength of the magnesium layer is ≤9.2, and the texture strength of the aluminum layer is ≤4.

2.

10. The magnesium-aluminum composite plate reinforced with a zinc intermediate layer according to claim 8, characterized in that: The magnesium-aluminum composite plate has an interface bonding strength of 75-90 MPa, a tensile strength of 320-340 MPa, and an elongation of 15-18%.

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