Method for improving the uniformity of the thickness of a magnesium / aluminum composite sheet and product thereof

Abstract

The application discloses a method for improving the thickness uniformity of a magnesium / aluminum composite plate and a product thereof, and belongs to the technical field of metal material composite processing. The method comprises the following steps: magnesium alloy plates and aluminum alloy plates are subjected to composite rolling by adopting differential friction regulation and temperature gradient, so that a magnesium / aluminum composite plate is obtained; the differential friction regulation is specifically that the friction coefficient of the friction functional layer coated on the surface of the magnesium alloy plate is 0.2-0.4 higher than that of the friction functional layer coated on the surface of the aluminum alloy plate; and the temperature gradient is specifically that the pretreatment temperature of the magnesium alloy plate is 50-100 DEG C higher than that of the aluminum alloy plate. That is to say, the magnesium / aluminum interlayer deformation rate can be effectively coordinated by the synergistic effect of the differential friction regulation-temperature gradient, the thickness uniformity is significantly improved, and the bonding stability is effectively improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal material composite processing, and particularly relates to a method for improving layer thickness uniformity of a magnesium / aluminum composite plate and a product thereof. BACKGROUND

[0002] Under the traditional magnesium / aluminum composite plate rolling process, due to the differences in mechanical properties, deformation resistance and interface friction characteristics of magnesium and aluminum, the interlayer deformation rate is not matched in the rolling process, the interlayer deformation is difficult to coordinate, and problems such as thickness fluctuation (±20%) of each layer, interface delamination, and significant difference in bonding performance of each region are often caused, which seriously restricts the size accuracy and mechanical properties of the composite plate and affects the component forming of the composite plate.

[0003] The interface friction coefficient is a key process parameter for regulating material plastic flow, temperature evolution and interface bonding quality. Under the traditional magnesium / aluminum composite plate rolling process, the critical reduction rate is large, and if the friction coefficient is not properly controlled, the lubrication condition of the contact interface is insufficient or the interface surface state is not matched, which will cause severe local shear deformation of the magnesium / aluminum interface at a large reduction rate, accompanied by a large amount of friction heat. Since the aluminum layer itself has good plasticity, low thermal conductivity and a lower melting point than the Mg layer, the local temperature rise is significant, and it is easy to exceed the solidus temperature under extreme conditions, resulting in melting or interface liquefaction of the aluminum layer. This kind of phenomenon will seriously damage the interface bonding state, induce interface cavitation, abnormal enrichment of intermetallic compounds and delamination, and seriously affect the structural integrity and service performance of the composite plate. In addition, due to the differences in thermal properties of magnesium and aluminum, the deformation of the heterogeneous metals is difficult to coordinate at the same rolling temperature and other parameters.

[0004] Therefore, it is urgent to provide a composite rolling method that can systematically regulate the interlayer friction and temperature field to realize the preparation of magnesium / aluminum composite plates with high uniformity and high quality. SUMMARY

[0005] In view of the above technical problems, the application provides a method for improving the layer thickness uniformity of a magnesium / aluminum composite plate and a product thereof. The synergistic effect of differential friction regulation and temperature gradient can effectively coordinate the interlayer deformation rate of magnesium and aluminum, significantly improve the thickness uniformity, and effectively improve the bonding stability.

[0006] To achieve the above-mentioned purpose, the application provides the following technical scheme:

[0007] One of the technical schemes of the application is as follows:

[0008] A method for improving the layer thickness uniformity of a magnesium / aluminum composite plate, comprising the following steps:

[0009] The magnesium alloy plate and the aluminum alloy plate are subjected to composite rolling by adopting differential friction regulation and temperature gradient, and a magnesium / aluminum composite plate is obtained.

[0010] The differential friction regulation is that the friction coefficient of the friction functional layer coated on the surface of the magnesium alloy plate is 0.2-0.4 higher than that of the friction functional layer coated on the surface of the aluminum alloy plate; and the temperature gradient is that the pretreatment temperature of the magnesium alloy plate is 50-100 DEG C higher than that of the aluminum alloy plate.

[0011] Beneficial effects: the present application realizes the high-quality continuous preparation of the magnesium / aluminum composite plate from the two aspects of the interface friction behavior and the thermal force coupling response by combining the method of differential friction regulation and temperature gradient design. Not only the problems such as interlayer slip, local melting and interface brittle phase generation in the traditional composite process are solved, but also the thickness uniformity, interface bonding strength and process stability of the product are significantly improved. The method has a wide process window, wide material adaptability and excellent engineering application prospect, and provides an innovative solution for the efficient and controllable preparation of dissimilar metal composite materials.

[0012] That is, the present application is important for realizing uniform plastic deformation, inhibiting abnormal heat input and guaranteeing solid-phase connection mechanism from the perspective of process optimization. And the reasonable matching of the lubricant type and application method and the rolling parameters (such as speed, temperature, reduction rate, etc.) is considered to minimize the thermal-force non-uniformity and avoid the metallurgical failure of the composite interface.

[0013] Optionally, the friction coefficient of the friction functional layer coated on the surface of the magnesium alloy plate is 0.3-0.5; and the friction coefficient of the friction functional layer coated on the surface of the aluminum alloy plate is 0.1-0.2.

[0014] Beneficial effects: the present application limits the differential friction to guide the magnesium alloy to deform plastically first, thereby driving the aluminum alloy to flow synchronously; inhibits the interlayer slip and reduces the interface shear strain; realizes the coordinated deformation of each layer of material and avoids the local stress concentration.

[0015] Further, the friction functional layer coated on the surface of the magnesium alloy plate is a ceramic coating or an emulsion layer.

[0016] Further, the friction functional layer coated on the surface of the aluminum alloy plate is a graphene coating, a synthetic oil layer or a rolling oil layer.

[0017] Optionally, the pretreatment temperature of the magnesium alloy plate is 370-420 DEG C; the pretreatment temperature of the aluminum alloy plate is 250-350 DEG C; and the holding time of the pretreatment of both is 0.5-2h.

[0018] Beneficial effects: magnesium alloy softens more fully at higher temperatures, which is conducive to its preferential deformation; aluminum alloy maintains a certain hardness to prevent premature melting; temperature gradient adjusts interface diffusion kinetics to promote atomic migration and interface bonding; while inhibiting the excessive generation of brittle intermetallic compounds (IMC).

[0019] Further, the magnesium alloy plate is selected from Mg-Al-Zn, Mg-Zn-Zr or Mg-Li magnesium alloy plate;

[0020] The aluminum alloy plate is selected from 1000 series, 5000 series, 6000 series or 7000 series aluminum alloy plate.

[0021] Further, the magnesium alloy plate is at least one of AZ31 magnesium alloy plate, LA141 magnesium alloy plate and ZK60 magnesium alloy plate; wherein, in the AZ31 magnesium alloy plate, A represents aluminum element, Z represents zinc element, and 3 and 1 represent the mass percentage of aluminum and zinc elements, respectively; in the LA141 magnesium alloy plate, L is Li element, A is Al element, and 14 and 1 represent the mass percentage of lithium and aluminum elements, respectively; in the ZK60 magnesium alloy plate, Z represents zinc element, K represents zirconium element, and 6 represents that the mass percentage of zinc element is about 4%, and 0 represents that the mass percentage of zirconium element is less than 1%.

[0022] The aluminum alloy plate is at least one of 6061 aluminum alloy plate, 7075 aluminum alloy plate, 5052 aluminum alloy plate or 1060 aluminum alloy plate.

[0023] Further, the size of the magnesium alloy plate and the aluminum alloy plate is: length of 50-2500mm, width of 20-1000mm, thickness of 2-16mm.

[0024] Optionally, the conditions in the composite rolling process are: rolling speed not less than 3 m / min (preferably 3-8 m / min), and rolling reduction of 40-60%.

[0025] Beneficial effects: by accurately controlling the rolling speed and reduction, solid phase connection of the composite interface is ensured; thereby avoiding the problem of brittle phase generation commonly seen in traditional liquid phase welding; and the interface bonding strength and stability are improved.

[0026] The second technical scheme of the present application is:

[0027] A magnesium / aluminum composite plate prepared by the above method.

[0028] Optionally, the thickness fluctuation of the magnesium / aluminum composite plate is less than ±5%, and the diffusion layer thickness is ≤15 μm.

[0029] Optionally, the shear strength of the magnesium / aluminum composite plate is ≥60 MPa, and the maximum can be up to 104 MPa.

[0030] Compared with the prior art, the application has the following advantages and technical effects:

[0031] The method proposed in the application realizes synchronous plastic flow of each layer of the composite plate through friction difference, effectively avoids interlayer slip, significantly reduces interface shear strain, thereby inhibiting local melting of the aluminum alloy and interface thermal instability; at the same time, relying on accurate regulation of the temperature gradient, regulation of interface diffusion dynamics is realized, coordinated deformation behavior between dissimilar metals is promoted, and generation of interface brittle intermetallic compounds is inhibited; that is, through the synergistic control method of differential friction-temperature gradient, the application successfully realizes a high-quality, strongly controllable continuous preparation process of the magnesium / aluminum composite plate, the product yield is greater than or equal to 90%, the process parameter window is wide, and multiple grades of magnesium alloys and aluminum alloys can be combined; moreover, the composite plate prepared by the application has good thickness uniformity (fluctuation less than ± 5%), high interface bonding rate (> 95%), shear strength is more than doubled compared with the traditional rolling process (when the magnesium and aluminum holding temperatures are the same, 400 DEG C, and the reduction rate is 50%, the shear strength of the composite plate is 48 MPa), and is suitable for subsequent secondary forming processing requirements, and has excellent engineering application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and serve as an appositive explanation of the illustrative embodiments of the present application, and shall not constitute an improper limitation of the present application. In the drawings:

[0033] Figure 1 is a macroscopic morphology diagram of the composite plate obtained in Example 1 of the present application;

[0034] Figure 2 is a comparison diagram of thickness uniformity of each layer of the magnesium / aluminum composite plate obtained in Example 1 and Comparative Examples 1-5;

[0035] Figure 3 is an interface micro-morphology diagram of the magnesium / aluminum composite plate obtained in Example 1, wherein (a) is the interface morphology of Example 1, (b) is an element scanning distribution diagram at the interface of Example 1, (c) is a line scanning position diagram at the interface of Example 1, and (d) is a line scanning distribution result diagram at the interface of Example 1;

[0036] Figure 4 is a shear strength curve diagram of the magnesium / aluminum composite plate at different positions of Example 1. DETAILED DESCRIPTION

[0037] The various exemplary embodiments of the present application will be described in detail below, which should not be considered as a limitation of the present application, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present application.

[0038] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of, for example, concentration, intensity, and time, an intermediate value of the range can be specifically recited herein; it is contemplated that it is within the scope of the application to set forth a range of values including each individual value within the range. The upper and lower limits of these smaller ranges can independently be included or excluded in the range.

[0039] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference for the disclosure and

[0040] Many modifications and variations of the present application described herein will be apparent to those of ordinary skill in the art from the foregoing description. Accordingly, it is to be understood that the application, in its broadest form, is not to be limited to the specific embodiments foreseen as illustrative herein. Rather, the specific embodiments are intended to illustrate the application and its best mode at the time of the patenting. Other embodiments within the scope of the present application will make themselves apparent to the skilled person reading the present specification. The specification and examples are to be considered exemplary only.

[0041] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean including, but not limited to.

[0042] The embodiments of the present application disclose a method for improving the thickness uniformity of a magnesium / aluminum composite plate, comprising the following steps:

[0043] Step 1: realizing friction difference regulation by coating a functional coating on the surface of a roller, wherein the friction coefficient of the roller contacted by the magnesium layer is higher than that of the aluminum layer; and wherein the friction regulation mode is a roller surface lubrication mode;

[0044] Step 2: respectively preheating the magnesium alloy plate and the aluminum alloy plate after polishing treatment, wherein the temperature of the magnesium alloy plate is higher than that of the aluminum alloy plate, a temperature gradient of 50-100 DEG C is formed, and the difference in interlayer rheological behavior is reduced;

[0045] Step 3: adjusting the rolling speed, and performing composite rolling on the stacked plates;

[0046] In some optional embodiments, the surface of the roller contacted by the magnesium layer in step 1 needs to be coated with a high-friction functional layer, such as a ceramic coating, and the friction coefficient is controlled to be 0.3-0.5;

[0047] The low friction functional layer, such as a graphene coating, is coated on the surface of the roller in contact with the aluminum layer, and the friction coefficient is controlled to be 0.1-0.2.

[0048] In some optional embodiments, in step 2, the plate has a length of 50-2500 mm, a width of 20-1000 mm, and a thickness of 2-16 mm, and the holding time is 0.5-2 h.

[0049] Further, the magnesium alloy is preheated to 370-420 DEG C, and the aluminum alloy plate is preheated to 250-350 DEG C.

[0050] In some optional embodiments, in step 3, the rolling speed is not less than 3 m / min, and the rolling reduction is 40-60%.

[0051] In some optional embodiments, the magnesium alloy plate is an Mg-Al-Zn system, Mg-Zn-Zr system or Mg-Li system magnesium alloy plate, and the aluminum alloy plate is a 1000 system, 5000 system, 6000 system or 7000 system aluminum alloy plate.

[0052] The application further discloses a magnesium / aluminum composite plate prepared by the method.

[0053] In some optional embodiments, the magnesium / aluminum composite plate has good interface bonding, no intermetallic compound is generated, and the diffusion layer has a thickness of less than or equal to 15 microns.

[0054] In some optional embodiments, the magnesium / aluminum composite plate has a shear strength of greater than or equal to 60 MPa.

[0055] The raw materials used in the application are all commercially available.

[0056] The technical solutions of the application are further described below through examples.

[0057] Example 1

[0058] A method for improving the layer thickness uniformity of a magnesium / aluminum composite plate, comprising the following steps:

[0059] AZ31 magnesium alloy plates and 6061 aluminum alloy plates are selected, and the initial sizes are 700*400*8 mm and 700*400*5 mm, respectively;

[0060] An Al2O3-based ceramic coating (friction coefficient 0.4) is uniformly coated on the surface of the roller in contact with the magnesium layer, and a high-temperature-resistant graphene coating (friction coefficient 0.15) is coated on the surface of the roller in contact with the aluminum side, so as to reduce the interface shear strain and inhibit the local melting of the aluminum alloy and the interface thermal instability phenomenon;

[0061] The magnesium alloy plate is kept at 380℃ for 1h, and the aluminum alloy plate is kept at 300℃ for 1h, so that a temperature gradient is formed between the different metals, and the deformation of the magnesium alloy plate and the aluminum alloy plate is coordinated;

[0062] The linear speed of the roller is set to 5 m / min; the composite single pass reduction rate is set to 53.8%; the different metals are stacked and rolled according to the above conditions, and the macro morphology of the composite plate after rolling is as shown in Figure 1 From Figure 1 It can be seen from the figure that after edge crack shearing, the length of the magnesium / aluminum composite plate is >1m, the width is 350mm, the surface quality is good, and the surface bonding rate is >95%.

[0063] Figure 2 The comparative diagram of the thickness uniformity of each layer of the magnesium / aluminum composite plate obtained in Example 1 and Comparative Examples 1-5; from the figure, it can be seen that the thickness of each layer in the rolling direction is observed by cutting, the total thickness of the composite plate after rolling in Example 1 is 6mm, the thickness fluctuation of the magnesium layer and the aluminum layer is controlled within ±5%, and the deformation amount of the magnesium plate and the aluminum plate is 52.5-53.1% and 55-57% respectively. Compared with Comparative Examples 1-5: it proves that the thickness fluctuation of each layer of the composite plate prepared by the present application is smaller; the deformation amount of the aluminum alloy is controlled by friction-temperature coordination, which promotes deformation coordination, and at the same time prevents local area of the aluminum layer from heating up sharply, preventing interface failure.

[0064] Figure 3 The interface micro-morphology diagram of the magnesium / aluminum composite plate obtained in Example 1, wherein (a) is the interface morphology of Example 1, (b) is the element scanning distribution diagram of the interface of Example 1, (c) is the line scanning position diagram of the interface of Example 1, and (d) is the line scanning distribution result diagram of the interface of Example 1; by SEM observation, the interface is well bonded, and no continuous brittle phase is observed;

[0065] Figure 4 The shear strength curve diagram of the magnesium / aluminum composite plate at different positions of Example 1 (the samples 1-3 in the figure are taken from different positions of the composite plate of Example 1); by shear strength test, the test standard is GB / T 33334-2016, and the average interface bonding strength is measured to be 101 MPa.

[0066] Comparative Example 1

[0067] The method is basically consistent with the method provided by Example 1 for optimizing the thickness uniformity of the magnesium / aluminum composite plate in operation and conditions, the difference lies in: the step of coating Al2O3-based ceramic coating on the roller surface contacted with the magnesium layer and coating high-temperature resistant graphene coating on the roller surface contacted with the aluminum side in Example 1 is omitted, and is replaced by smearing commercial rolling oil (friction coefficient 0.2) on the roller surface contacted with the magnesium layer and the aluminum layer.

[0068] The experimental results show that after rolling, the deformation of magnesium and aluminum plates is 45.1-54.4% and 53.1-67.8% respectively, the surface bonding rate is > 85%, and the thickness uniformity of each layer of the composite plate is poor, with a fluctuation of > 25% (as shown in Figure 2 The interface bonding strength is poor, and the test shows that the interface bonding strength is 52 MPa.

[0069] Comparative Example 2

[0070] The method is basically consistent with the method provided in Example 1 for optimizing the thickness uniformity of the magnesium / aluminum composite plate in terms of operation and conditions, except that the step of coating the Al2O3-based ceramic coating on the surface of the roller contacting the magnesium layer and the high-temperature resistant graphene coating on the surface of the roller contacting the aluminum layer in Example 1 is omitted, and is replaced by smearing emulsion (friction coefficient 0.3) on the surface of the roller contacting the magnesium layer and the aluminum layer.

[0071] The experimental results show that after rolling, the deformation of magnesium and aluminum plates is 46.2-58.2% and 47.2-66.3% respectively, the surface bonding rate is < 60%, and the thickness uniformity of each layer of the composite plate is poor, with a fluctuation of > 35% (as shown in Figure 2 The interface bonding strength is poor, and the test shows that the interface bonding strength is only 34 MPa.

[0072] Comparative Example 3

[0073] The method is basically consistent with the method provided in Example 1 for optimizing the thickness uniformity of the magnesium / aluminum composite plate in terms of operation and conditions, except that the step of coating the Al2O3-based ceramic coating on the surface of the roller contacting the magnesium layer and the high-temperature resistant graphene coating on the surface of the roller contacting the aluminum layer in Example 1 is omitted, and is replaced by smearing the high-temperature resistant graphene coating (friction coefficient 0.15) on the surface of the roller contacting the magnesium layer and the aluminum layer.

[0074] The experimental results show that after rolling, the deformation of magnesium and aluminum plates is 52.2-54.3% and 53.3-58.2% respectively, the surface bonding rate is > 95%, and the thickness uniformity of each layer of the composite plate is poor, with a fluctuation of > 10% (as shown in Figure 2 The test shows that the interface bonding strength is 92 MPa.

[0075] Comparative Example 4

[0076] The method is basically consistent with the method provided in Example 1 for optimizing the thickness uniformity of the magnesium / aluminum composite plate in terms of operation and conditions, except that the step of coating the Al2O3-based ceramic coating on the surface of the roller contacting the magnesium layer and the high-temperature resistant graphene coating on the surface of the roller contacting the aluminum layer in Example 1 is omitted, and is replaced by smearing the Al2O3-based ceramic coating (friction coefficient 0.4) on the surface of the roller contacting the magnesium layer and the aluminum layer.

[0077] The experimental results show that after rolling, the deformation of magnesium and aluminum plates is 41.8-54.1% and 53.4-73.0%, respectively, the surface bonding rate is <65%, and the thickness uniformity of each layer of the composite plate is poor, with a fluctuation of >40% (as shown in the figure). Figure 2 The local area of the aluminum layer is heated sharply and melted, and the interface cracks.

[0078] Comparative Example 5

[0079] The method is basically consistent with the method provided in Example 1 for optimizing the layer thickness uniformity of the magnesium / aluminum composite plate in terms of operation and conditions, except that the step of coating the Al2O3-based ceramic coating on the roller surface in contact with the magnesium layer and the high-temperature resistant graphene coating on the roller surface in contact with the aluminum layer in Example 1 is omitted, i.e., no lubricating liquid (friction coefficient >0.5) is applied to the roller surface in contact with the magnesium layer and the aluminum layer.

[0080] The experimental results show that after rolling, the deformation of magnesium and aluminum plates is 41.8-57.5% and 48.0-73.0%, respectively, the surface bonding rate is <60%, and the thickness uniformity of each layer of the composite plate is poor, with a fluctuation of >50% (as shown in the figure). Figure 2 The local area of the aluminum layer is heated sharply and melted, and the interface cracks.

[0081] Comparative Example 6

[0082] The method is basically consistent with the method provided in Example 1 for optimizing the layer thickness uniformity of the magnesium / aluminum composite plate in terms of operation and conditions, except that the step of coating the Al2O3-based ceramic coating on the roller surface in contact with the magnesium layer and the high-temperature resistant graphene coating on the roller surface in contact with the aluminum layer in Example 1 is omitted, and is replaced by applying poly-alpha-olefin synthetic base oil (friction coefficient 0.1) to the roller surface in contact with the magnesium layer and the aluminum layer.

[0083] The experimental results show that under the set reduction conditions, the friction coefficient is too low, and the slab cannot be engaged.

[0084] Comparative Example 7

[0085] The method is basically consistent with the method provided in Example 1 for optimizing the layer thickness uniformity of the magnesium / aluminum composite plate in terms of operation and conditions, except that the preheating temperature of the magnesium alloy plate and the aluminum alloy plate is changed, i.e., the magnesium alloy plate and the aluminum alloy plate are kept at 400°C for 1 h before rolling.

[0086] The experimental results show that after rolling, the deformation of magnesium and aluminum plates is 37.5-46.2% and 66.0-80.0%, respectively, the deformation of the aluminum alloy is increased by 40.5% compared with Example 1, and the surface bonding rate is >95%. After testing, the interface bonding strength is 86 MPa.

[0087] Comparative Example 8

[0088] The method is basically consistent with the operation and conditions of the method for optimizing the layer thickness uniformity of the magnesium / aluminum composite plate provided in Example 1, except that the preheating temperature of the magnesium alloy plate and the aluminum alloy plate is changed, that is, the magnesium alloy plate and the aluminum alloy plate are kept at 350°C for 1 h before rolling.

[0089] The experimental results show that the surface bonding rate is less than 70%, and the interface bonding strength is 39 MPa after testing.

[0090] Comparative Example 9

[0091] The method is basically consistent with the operation and conditions of the method for optimizing the layer thickness uniformity of the magnesium / aluminum composite plate provided in Example 1, except that the preheating temperature of the magnesium alloy plate and the aluminum alloy plate is changed, that is, the magnesium alloy plate and the aluminum alloy plate are kept at 300°C for 1 h before rolling.

[0092] The experimental results show that the magnesium alloy plate cannot be bonded.

[0093] Comparative Example 10

[0094] The method is basically consistent with the operation and conditions of the method for optimizing the layer thickness uniformity of the magnesium / aluminum composite plate provided in Example 1, except that the preheating temperature of the magnesium alloy plate and the aluminum alloy plate is changed, that is, the magnesium alloy plate is kept at 450°C for 1 h, and the aluminum alloy plate is kept at 250°C for 1 h before rolling.

[0095] The experimental results show that the magnesium alloy plate material grain coarsens, and a large number of transverse and reticular cracks occur during rolling, and the surface bonding rate is less than 30%.

[0096] Example 2

[0097] The LA141 magnesium alloy plate and the 7075 aluminum alloy plate are selected, and the initial sizes are 1000x600x16mm and 1000x600x3mm, respectively;

[0098] Emulsified liquid (friction coefficient 0.3) is applied to the surface of the roller in contact with the magnesium layer, and poly-alpha-olefin synthetic base oil (friction coefficient 0.1) is applied to the surface of the roller in contact with the aluminum side;

[0099] The magnesium alloy plate is kept at 400°C for 1 h, and the aluminum alloy plate is kept at 350°C for 1 h;

[0100] The roller linear speed is set to 4 m / min; the composite single pass reduction rate is set to 40%; the heterogeneous metals are stacked and rolled according to the above conditions, the surface bonding rate is greater than 95%, the thickness fluctuation of the magnesium layer and the aluminum layer is controlled within ±4%; through shear strength test, the interface bonding strength is 63 MPa.

[0101] Example 3

[0102] ZK60 magnesium alloy plate and 5052 aluminum alloy plate are selected, and the initial sizes are 1000*300*6mm and 1000*300*15mm respectively;

[0103] The roller surface in contact with the magnesium layer is coated with an Al2O3-based ceramic coating (friction coefficient 0.4), and the roller surface in contact with the aluminum side is coated with a commercial rolling oil (friction coefficient 0.2);

[0104] The magnesium alloy plate is kept at 420℃ for 1h, and the aluminum alloy plate is kept at 350℃ for 1h;

[0105] The roller linear velocity is set to 5 m / min; the composite single pass reduction rate is set to 50%; the heterogeneous metals are stacked and rolled according to the above conditions, the surface bonding rate is >95%, the thickness fluctuation of the magnesium layer and the aluminum layer is controlled within ±4%; through shear strength test, the interface bonding strength is 72 MPa.

[0106] Example 4

[0107] AZ31 magnesium alloy plate and 1060 aluminum alloy plate are selected, and the initial sizes are 1000*300*6mm and 1000*300*6mm respectively;

[0108] The roller surface in contact with the magnesium layer is coated with an Al2O3-based ceramic coating (friction coefficient 0.4), and the roller surface in contact with the aluminum side is coated with a high-temperature-resistant graphene coating (friction coefficient 0.15);

[0109] The magnesium alloy plate is kept at 370℃ for 1h, and the aluminum alloy plate is kept at 250℃ for 1h;

[0110] The roller linear velocity is set to 6 m / min; the composite single pass reduction rate is set to 50%; the heterogeneous metals are stacked and rolled according to the above conditions, the surface bonding rate is >95%, the thickness fluctuation of the magnesium layer and the aluminum layer is controlled within ±4%; through shear strength test, the interface bonding strength is 84 MPa.

[0111] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for improving the uniformity of thickness in magnesium / aluminum composite plates, characterized in that, Includes the following steps: A magnesium / aluminum composite plate is obtained by composite rolling of magnesium alloy plate and aluminum alloy plate by using differential friction to control the synergistic temperature gradient. The differential friction control specifically involves the following: the friction coefficient of the friction functional layer coated on the roller surface in contact with the magnesium alloy plate is 0.2-0.4 higher than that of the friction functional layer coated on the roller surface in contact with the aluminum alloy plate; the friction coefficient of the friction functional layer coated on the roller surface in contact with the magnesium alloy plate is 0.3-0.5; and the friction coefficient of the friction functional layer coated on the roller surface in contact with the aluminum alloy plate is 0.1-0.

2. The temperature gradient is as follows: the pretreatment temperature of the magnesium alloy plate is 50-100℃ higher than that of the aluminum alloy plate; the pretreatment temperature of the magnesium alloy plate is 370-420℃; the pretreatment temperature of the aluminum alloy plate is 250-350℃; and the heat preservation time for both pretreatments is 0.5-2h.

2. The method for improving the uniformity of magnesium / aluminum composite plate layer thickness according to claim 1, characterized in that, The friction functional layer coated on the roller surface where the magnesium alloy plate contacts the roller is a ceramic coating or an emulsion layer.

3. The method for improving the uniformity of magnesium / aluminum composite plate layer thickness according to claim 1, characterized in that, The friction functional layer coated on the roller surface in contact with the aluminum alloy plate is a graphene coating, a synthetic oil layer, or a rolling oil layer.

4. The method for improving the uniformity of magnesium / aluminum composite plate layer thickness according to claim 1, characterized in that, The magnesium alloy plate is selected from Mg-Al-Zn series, Mg-Zn-Zr series or Mg-Li series magnesium alloy plates; The aluminum alloy sheet is selected from 1000 series, 5000 series, 6000 series or 7000 series aluminum alloy sheets.

5. A method for improving the uniformity of magnesium / aluminum composite plate layer thickness according to claim 4, characterized in that, The magnesium alloy plate is at least one of AZ31 magnesium alloy plate, LA141 magnesium alloy plate, and ZK60 magnesium alloy plate; The aluminum alloy plate is at least one of 6061 aluminum alloy plate, 7075 aluminum alloy plate, 5052 aluminum alloy plate or 1060 aluminum alloy plate.

6. A method for improving the uniformity of magnesium / aluminum composite plate layer thickness according to claim 1, characterized in that, The conditions for the composite rolling process are: rolling speed of 3-8 m / min and rolling reduction of 40-60%.

7. A magnesium / aluminum composite plate, characterized in that, Prepared by the method described in any one of claims 1-6.

8. A magnesium / aluminum composite plate according to claim 7, characterized in that, The thickness fluctuation of the magnesium / aluminum composite plate is less than ±5%; the diffusion layer thickness is ≤15 μm; and the bonding strength is ≥60 MPa.

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