Aluminum alloy multi-layer composite plate and its preparation method and application

Abstract

The present invention provides an aluminum alloy multi-layer composite plate, a preparation method thereof and an application. The aluminum alloy multi-layer composite plate includes a first layer, a second layer, a third layer and a fourth layer stacked in sequence; wherein, the first layer and the third layer are both 3XXX series aluminum alloys, the second layer is a 6XXX series aluminum alloy, and the fourth layer is a 4XXX series aluminum alloy. By mass percentage, the 6XXX series aluminum alloy includes the following elements: Si element, Mg element, Cu element, Zn element, Mn element, Zr element, Cr element, Ti element, Fe element and Al element. Arranging the 6XXX series aluminum alloy between the 3XXX series aluminum alloys helps to prevent the high-temperature volatilization of the Mg element in the 6XXX series aluminum alloy, thereby helping to improve the high-temperature resistance of the aluminum alloy multi-layer composite plate. The aluminum alloy multi-layer composite plate of the present application not only has high yield strength, tensile strength and elongation, but also has a low cost.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular, to an aluminum alloy multi-layer composite plate, a preparation method thereof, and an application thereof. Background Art

[0002] During the charge and discharge process of the power battery of new energy vehicles, a large amount of heat will be generated. Excessive temperature will affect the performance, life, and safety of the battery. The liquid cooling plate can efficiently take away the heat generated by the battery and keep the battery working within an appropriate temperature range. With the continuous expansion of the new energy vehicle market and the increasing requirements of consumers for the cruising range and battery safety, the application proportion of the liquid cooling plate in the battery thermal management of new energy vehicles will continue to increase; in addition, with the rapid development of the energy storage industry, the heat generated during the charge and discharge of the energy storage system battery needs to be transferred immediately to keep the battery system operating within a safe temperature range, which also poses higher requirements for the liquid cooling plate.

[0003] The traditional brazed plate composite plate for heat exchange is mainly 4XXX / 3XXX composite plate. Among them, the 3XXX series aluminum alloy is an Al-Mn alloy with low strength, and mainly 3003 alloy and its modified alloys are selected. The 4XXX series aluminum alloy is an Al-Si alloy, which completely melts when brazed at a temperature above 600 °C to fill the joint gap and play a connecting role; the 4XXX / 3XXX composite plate has poor anti-collapse ability and low yield strength at high temperature brazing, only about 50 MPa. The strength and stiffness of the actually produced liquid cooling plate are insufficient, and it is difficult to support the weight of the battery module, and a steel support structure needs to be matched for reinforcement, resulting in a large increase in weight, and the lightweight effect is difficult to meet the industry requirements. Summary of the Invention

[0004] The main purpose of the present invention is to provide an aluminum alloy multi-layer composite plate, a preparation method thereof, and an application thereof to solve the problem of low yield strength existing in the aluminum alloy multi-layer composite plate in the prior art.

[0005] To achieve the above object, according to one aspect of the present invention, there is provided an aluminum alloy multi-layer composite plate, which includes a first layer, a second layer, a third layer, and a fourth layer stacked in sequence; wherein, the first layer and the third layer are both 3XXX series aluminum alloys, the second layer is a 6XXX series aluminum alloy, and the fourth layer is a 4XXX series aluminum alloy. By mass percentage, the 6XXX series aluminum alloy includes the following elements: the content of Si element is 0.3-0.7%, the content of Mg element is 0.6-0.9%, the content of Cu element is 0.1-0.3%, the content of Zn element is 0.05-0.3%, the content of Mn element is 0.01-0.15%, the content of Zr element is 0.01-0.08%, the content of Cr element is 0.001-0.1%, the content of Ti element is 0.001-0.04%, the content of Fe element is 0.05-0.6%, and the content of Si element is lower than that of Mg element. The total content of inevitable impurities ≤ 0.15wt%, the content of a single impurity is lower than 0.05wt%, and the balance is Al element.

[0006] Further, by mass percentage, the above 6XXX series aluminum alloy includes the following elements: the content of Si element is 0.45-0.7%, the content of Mg element is 0.8-0.9%, the content of Cu element is 0.15-0.25%, the content of Zn element is 0.15-0.25%, the content of Mn element is 0.02-0.15%, the content of Zr element is 0.04-0.08%, the content of Cr element is 0.01-0.1%, the content of Ti element is 0.03-0.04%, the content of Fe element is 0.25-0.6%, and the content of Si element is lower than that of Mg element. The total content of inevitable impurities ≤ 0.15wt%, the content of a single impurity is lower than 0.05wt%, and the balance is Al element.

[0007] Further, the mass ratio of the above Si element to the Mg element is (0.50-0.76):1; and / or, the mass ratio of the Cu element to the Zn element is (1-2):1; and / or, the mass ratio of the Mn element, the Zr element, and the Cr element is 1:(0.27-4):(0.5-0.7); and / or, the 3XXX series aluminum alloy is selected from any one or more of 3003 alloy, 3004 alloy, and 3105 alloy; and / or, the 4XXX series aluminum alloy is selected from any one or more of 4004 alloy, 4045 alloy, 4047 alloy, 4104 alloy, 4147 alloy, and 4343 alloy.

[0008] Furthermore, the thickness of the above aluminum alloy multi-layer composite plate is 0.5 - 2.0 mm; and / or, the average grain size of the aluminum alloy multi-layer composite plate is 80 - 90 μm; and / or, the yield strength of the aluminum alloy multi-layer composite plate is ≥156 MPa; and / or, the tensile strength of the aluminum alloy multi-layer composite plate is ≥205 MPa; and / or, the elongation of the aluminum alloy multi-layer composite plate is ≥14.3%.

[0009] According to another aspect of the present invention, there is provided a method for preparing the above-mentioned aluminum alloy multi-layer composite plate, and the preparation method includes: Step S1, sequentially performing slitting and first hot rolling on the 3XXX series aluminum alloy ingot to obtain the first hot rolled plate and the third hot rolled plate, performing surface milling on the 6XXX series aluminum alloy ingot to obtain the second cast plate, and performing third hot rolling on the 4XXX series aluminum alloy ingot to obtain the fourth hot rolled plate; Step S2, sequentially stacking the first hot rolled plate, the second cast plate, the third hot rolled plate, and the fourth hot rolled plate, and then sequentially performing welding fixation, second hot rolling, cold rolling, and annealing treatments to obtain the aluminum alloy multi-layer composite plate.

[0010] Furthermore, the thickness ratio of the above first hot rolled plate, second cast plate, third hot rolled plate, and fourth hot rolled plate is (90 - 100):(400 - 410):(66 - 76):(39 - 49).

[0011] Furthermore, the temperature of the above second hot rolling treatment is 480 - 490 °C; and / or, the thickness of the plate after the second hot rolling treatment is 3.0 - 6.0 mm; and / or, the temperature of the annealing treatment is 380 - 440 °C; and / or, the holding time of the annealing treatment is 4 - 6 h.

[0012] Furthermore, the above Step S2 further includes sequentially performing brazing treatment and aging treatment on the plate obtained after the annealing treatment to obtain the aluminum alloy multi-layer composite plate.

[0013] Furthermore, the temperature of the above brazing treatment is 600 - 625 °C; and / or, the holding time of the brazing treatment is 20 - 60 min; and / or, the temperature of the aging treatment is 200 - 240 °C; and / or, the holding time of the aging treatment is 20 - 40 min.

[0014] According to yet another aspect of the present invention, there is provided the application of the above-mentioned aluminum alloy multi-layer composite plate in a liquid cooling plate.

[0015] Applying the technical solution of the present invention, this application arranges the 6XXX series aluminum alloy between the 3XXX series aluminum alloys, which helps to prevent the high-temperature volatilization of Mg elements in the 6XXX series aluminum alloy, thereby contributing to improving the high-temperature resistance of the aluminum alloy multi-layer composite plate. Moreover, the 3XXX series aluminum alloy has high corrosion resistance. Arranging the 6XXX series aluminum alloy between the 3XXX series aluminum alloys helps to improve the corrosion resistance of the aluminum alloy multi-layer composite plate. The function of the 4XXX series aluminum alloy enables the aluminum alloy multi-layer composite plate to be brazed and connected with other aluminum alloy plates. Controlling the contents of Mg elements and Si elements in the 6XXX series aluminum alloy within the above ranges and controlling the content of Si elements to be lower than that of Mg elements helps to promote the formation of strengthening phases by Mg elements and Si elements, thereby contributing to improving the yield strength, tensile strength, and elongation of the aluminum alloy multi-layer composite plate. Controlling the contents of Cu elements and Zn elements in the 6XXX series aluminum alloy within the above ranges helps to promote the formation of strengthening phases between Cu elements and Zn elements and aluminum elements, thereby contributing to further improving the yield strength, tensile strength, and elongation of the aluminum alloy multi-layer composite plate. The presence of Mn elements, Zr elements, and Cr elements helps to refine the grains. Controlling the contents of Mn elements, Zr elements, and Cr elements within the above ranges helps to cooperate synergistically with other elements in the 6XXX series aluminum alloy, thereby contributing to further refining the grains and further contributing to improving the yield strength, tensile strength, and elongation of the aluminum alloy multi-layer composite plate. In addition, this application can have a relatively high iron content, which helps to reduce the production cost of the aluminum alloy multi-layer composite plate. Therefore, the aluminum alloy multi-layer composite plate of this application not only has high yield strength, tensile strength, and elongation but also has a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The specification drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0017] Figure 1 shows the schematic structural diagram of the aluminum alloy multi-layer composite plate in Embodiment 1 of this application;

[0018] Figure 2 shows the metallographic structure diagram of the aluminum alloy multi-layer composite plate in Embodiment 1 of this application;

[0019] Figure 3 shows the schematic structural diagram of the liquid cooling plate of this application.

[0020] Among them, the above-mentioned drawings include the following reference numerals:

[0021] 1, the first layer; 2, the second layer; 3, the third layer; 4, the fourth layer; 5, the cover plate; 6, the brazing plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0023] As analyzed in the background art of this application, there is a problem of low yield strength in the existing aluminum alloy multi-layer composite plates. To solve the above problems, this application provides an aluminum alloy multi-layer composite plate, its preparation method and application.

[0024] In a typical implementation manner of this application, an aluminum alloy multi-layer composite plate is provided. As Figure 1 shown, the aluminum alloy multi-layer composite plate includes a first layer 1, a second layer 2, a third layer 3, and a fourth layer 4 stacked in sequence; wherein, both the first layer and the third layer are 3XXX series aluminum alloys, the second layer is a 6XXX series aluminum alloy, and the fourth layer is a 4XXX series aluminum alloy. By mass percentage, the 6XXX series aluminum alloy includes the following elements: the content of Si element is 0.3 - 0.7%, the content of Mg element is 0.6 - 0.9%, the content of Cu element is 0.1 - 0.3%, the content of Zn element is 0.05 - 0.3%, the content of Mn element is 0.01 - 0.15%, the content of Zr element is 0.01 - 0.08%, the content of Cr element is 0.001 - 0.1%, the content of Ti element is 0.001 - 0.04%, the content of Fe element is 0.05 - 0.6%, and the content of Si element is lower than the content of Mg element. The total content of inevitable impurities ≤ 0.15wt%, the content of a single impurity is lower than 0.05wt%, and the balance is Al element.

[0025] In this application, the 6XXX series aluminum alloy is disposed between the 3XXX series aluminum alloys, which helps prevent the high-temperature volatilization of the Mg element in the 6XXX series aluminum alloy, thereby contributing to improving the high-temperature resistance of the multi-layer composite aluminum alloy plate. Moreover, the 3XXX series aluminum alloy has high corrosion resistance. Disposing the 6XXX series aluminum alloy between the 3XXX series aluminum alloys helps improve the corrosion resistance of the multi-layer composite aluminum alloy plate. The function of the 4XXX series aluminum alloy enables the multi-layer composite aluminum alloy plate to be brazed and connected to other aluminum alloy plates. Controlling the contents of the Mg element and the Si element in the 6XXX series aluminum alloy within the above ranges and controlling the content of the Si element to be lower than that of the Mg element helps promote the formation of strengthening phases by the Mg element and the Si element, thereby contributing to improving the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate. Controlling the contents of the Cu element and the Zn element in the 6XXX series aluminum alloy within the above ranges helps promote the formation of strengthening phases between the Cu element and the Zn element and the aluminum element, thereby contributing to further improving the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate. The presence of the Mn element, Zr element, and Cr element helps refine the grains. Controlling the contents of the Mn element, Zr element, and Cr element within the above ranges helps cooperate synergistically with other elements in the 6XXX series aluminum alloy, thereby contributing to further refining the grains and further contributing to improving the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate. In addition, this application can have a relatively high iron content, which helps reduce the production cost of the multi-layer composite aluminum alloy plate. Therefore, the multi-layer composite aluminum alloy plate of this application not only has high yield strength, tensile strength, and elongation but also has a low cost.

[0026] In order to further improve the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate, in an embodiment of this application, by mass percentage, preferably the above 6XXX series aluminum alloy includes the following elements: the content of the Si element is 0.45 - 0.7%, the content of the Mg element is 0.8 - 0.9%, the content of the Cu element is 0.15 - 0.25%, the content of the Zn element is 0.15 - 0.25%, the content of the Mn element is 0.02 - 0.15%, the content of the Zr element is 0.04 - 0.08%, the content of the Cr element is 0.01 - 0.1%, the content of the Ti element is 0.03 - 0.04%, the content of the Fe element is 0.25 - 0.6%, and the content of the Si element is lower than that of the Mg element. The total content of inevitable impurities ≤ 0.15 wt%, the content of a single impurity is lower than 0.05 wt%, and the balance is the Al element.

[0027] In an embodiment of the present application, the mass ratio of the above Si element to the Mg element is (0.50 - 0.76):1, specifically, it can be 0.50:1, 0.55:1, 0.60:1, 0.65:1, 0.70:1, 0.76:1, and the range values between any two ratios; and / or, the mass ratio of the Cu element to the Zn element is (1 - 2):1, specifically, it can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, and the range values between any two ratios; and / or, the mass ratio of the Mn element, Zr element and Cr element is 1:(0.27 - 4):(0.5 - 0.7); and / or, the 3XXX series aluminum alloy is selected from any one or more of 3003 alloy, 3004 alloy and 3105 alloy; and / or, the 4XXX series aluminum alloy is selected from any one or more of 4004 alloy, 4045 alloy, 4047 alloy, 4104 alloy, 4147 alloy and 4343 alloy.

[0028] Controlling the mass ratio of the Si element to the Mg element within the above range helps to further improve the interaction between the Si element and the Mg element, thereby helping to further promote the formation of strengthening phases by the Mg element and the Si element, and further helping to improve the yield strength, tensile strength and elongation of the aluminum alloy multi-layer composite plate. Controlling the mass ratio of the Cu element to the Zn element within the above range helps to further improve the interaction between the Cu element and the Zn element, thereby helping to further promote the formation of strengthening phases between the Cu element and the Zn element and the aluminum element, and further helping to further improve the yield strength, tensile strength and elongation of the aluminum alloy multi-layer composite plate. Controlling the mass ratio of the Mn element, Zr element and Cr element within the above range helps to improve the interaction between the Mn element, Zr element and Cr element, thereby helping to further refine the grains, and further helping to further improve the yield strength, tensile strength and elongation of the aluminum alloy multi-layer composite plate.

[0029] In an embodiment of the present application, the mass ratio of the above Ti element to the Fe element is (0.10 - 0.15):1, specifically, it can be 0.10:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1, and the range values between any two ratios.

[0030] The presence of Ti element helps to stabilize the precipitates in the material, reduce the aggregation of precipitates during the aging treatment, and contribute to improving their uniform distribution. The presence of Fe element helps to promote the stability of these precipitates and further improve the strength and hardness of the material. Controlling the mass ratio of Ti element to Fe element within the above range helps to optimize the distribution of the precipitation strengthening phase, thereby contributing to further improving the yield strength, tensile strength and elongation of the aluminum alloy multi-layer composite plate.

[0031] In an embodiment of the present application, the thickness of the above-mentioned aluminum alloy multi-layer composite plate is 0.5-2.0 mm; and / or, the average grain size of the aluminum alloy multi-layer composite plate is 80-90 μm; and / or, the yield strength of the aluminum alloy multi-layer composite plate ≥156 MPa; and / or, the tensile strength of the aluminum alloy multi-layer composite plate ≥205 MPa; and / or, the elongation of the aluminum alloy multi-layer composite plate ≥14.3%; preferably, the yield strength of the aluminum alloy multi-layer composite plate is 167-175 MPa; and / or, the tensile strength of the aluminum alloy multi-layer composite plate is 215-219 MPa; and / or, the elongation of the aluminum alloy multi-layer composite plate is 15.2-15.5%.

[0032] Controlling the thickness of the aluminum alloy multi-layer composite plate within the above range helps to improve the stamping performance of the aluminum alloy multi-layer composite plate. Controlling the average grain size of the aluminum alloy multi-layer composite plate within the above range helps to further improve the yield strength, tensile strength and elongation of the aluminum alloy multi-layer composite plate. The aluminum alloy multi-layer composite plate with the above yield strength, tensile strength and elongation is more suitable for liquid cooling plates.

[0033] In a typical embodiment of the present application, a method for preparing the above-mentioned aluminum alloy multi-layer composite plate is provided. The preparation method includes: Step S1, sequentially cutting and first hot rolling a 3XXX series aluminum alloy ingot to obtain a first hot rolled plate and a third hot rolled plate, milling a 6XXX series aluminum alloy ingot to obtain a second cast plate, and performing a third hot rolling treatment on a 4XXX series aluminum alloy ingot to obtain a fourth hot rolled plate; Step S2, sequentially stacking the first hot rolled plate, the second cast plate, the third hot rolled plate and the fourth hot rolled plate, and then sequentially performing welding fixation, second hot rolling treatment, cold rolling treatment and annealing treatment to obtain an aluminum alloy multi-layer composite plate.

[0034] In step S1, the 3XXX series aluminum alloy ingot, 6XXX series aluminum alloy ingot, and 4XXX series aluminum alloy ingot are pretreated to obtain the first-layer hot-rolled plate, second-layer casting plate, third-layer hot-rolled plate, and fourth-layer hot-rolled plate with appropriate specifications. In step S2, the first-layer hot-rolled plate, second-layer casting plate, third-layer hot-rolled plate, and fourth-layer hot-rolled plate are stacked in sequence and then welded and fixed, which helps to tightly combine the first-layer hot-rolled plate, second-layer casting plate, third-layer hot-rolled plate, and fourth-layer hot-rolled plate together, forming a firm interlayer interface. The second hot-rolling treatment helps to promote the uniform distribution of alloying elements in the aluminum matrix, and at the same time, the grains are refined, which is beneficial to the formation of a microstructure that improves the strength and ductility of the material. The cold-rolling treatment helps to precisely control the thickness of the multi-layer aluminum alloy composite plate and improve the surface finish of the multi-layer aluminum alloy composite plate. The annealing treatment helps to eliminate the work hardening generated during the cold-rolling process and restore the plasticity of the material, thereby helping to reduce the cracking of the multi-layer aluminum alloy composite plate during the stamping process.

[0035] In an embodiment of the present application, the thickness ratio of the above-mentioned first-layer hot-rolled plate, second-layer casting plate, third-layer hot-rolled plate, and fourth-layer hot-rolled plate is (90~100):(400~410):(66~76):(39~49).

[0036] The 6XXX series aluminum alloy of the second-layer casting plate provides corresponding strength for the composite plate. The 3XXX series aluminum alloy in the first-layer hot-rolled plate and the third-layer hot-rolled plate serves as a protective layer, which helps to reduce the high-temperature volatilization of Mg elements in the second-layer casting plate and improve the performance stability of the composite plate. The 4XXX series aluminum alloy of the fourth-layer hot-rolled plate serves as a solder layer, which helps to improve the bonding force between the composite plate and other aluminum alloy plates. Controlling the thickness ratio of the first-layer hot-rolled plate, second-layer casting plate, third-layer hot-rolled plate, and fourth-layer hot-rolled plate within the above range helps to fully exert the interaction between the components, thereby helping to improve the yield strength, tensile strength, and elongation of the multi-layer aluminum alloy composite plate while improving the stamping performance of the multi-layer aluminum alloy composite plate.

[0037] In an embodiment of the present application, the temperature of the above-mentioned second hot-rolling treatment is 480~490°C; and / or, the thickness of the plate after the second hot-rolling treatment is 3.0~6.0 mm; and / or, the temperature of the annealing treatment is 380~440°C; and / or, the holding time of the annealing treatment is 4~6 h.

[0038] Controlling the temperature of the second hot rolling process within the above range helps to promote the uniform distribution of alloying elements while ensuring the plasticity of the material, reduce the abnormal growth of grains, and thus helps to optimize the microstructure of the composite plate and enhance the interfacial bonding strength. Controlling the thickness of the plate after the second hot rolling process within the above range helps to provide a good foundation for the subsequent cold rolling process, improve the deformation uniformity of the material during cold rolling, and reduce the risk of crack or delamination generation. Controlling the temperature and holding time of the annealing process within the above range helps to eliminate work hardening during cold rolling and reduce the risk of alloying element decomposition and property degradation that may be brought about by high temperatures.

[0039] In one embodiment of the present application, the above step S2 further includes sequentially performing brazing treatment and aging treatment on the plate obtained after annealing treatment to obtain an aluminum alloy multi-layer composite plate.

[0040] Through the brazing treatment, it helps to enhance the bonding strength between the layers of the composite plate and improve the stability and load-bearing capacity of the overall structure. The aging treatment helps to improve the uniformity of the distribution of precipitation phases in the alloy, and thus helps to improve the yield strength, tensile strength, and elongation of the material.

[0041] In one embodiment of the present application, the temperature of the above brazing treatment is 600~625 °C; and / or, the holding time of the brazing treatment is 20~60 min; and / or, the temperature of the aging treatment is 200~240 °C; and / or, the holding time of the aging treatment is 20~40 min.

[0042] Controlling the temperature and holding time of the brazing treatment within the above range helps to reduce the risk of overburning of the 6XXX series aluminum alloy during the brazing treatment and helps to control the mechanical properties of the 6XXX series aluminum alloy from being damaged. Controlling the temperature and holding time of the aging treatment within the above range helps to promote the uniform distribution of precipitation phases in the 6XXX series aluminum alloy, and these precipitation phases can significantly enhance the hardness and strength of the material without sacrificing its ductility excessively.

[0043] In a typical embodiment of the present application, the above-mentioned aluminum alloy multi-layer composite plate is provided for use in a liquid cooling plate.

[0044] The aluminum alloy multi-layer composite plate of the present application can be used to manufacture liquid cooling plates in the field of new energy vehicle battery thermal management and liquid cooling plates in the field of energy storage systems, such as Figure 3 The shown liquid cooling plate includes a cover plate 5 and a brazed plate 6, and the brazed plate 6 is obtained by stamping the aluminum alloy multi-layer composite plate of the present application.

[0045] The beneficial effects of the present application will be further described below in conjunction with embodiments.

[0046] Example 1

[0047] In terms of mass percentage, the element ratio of the 6XXX series alloy ingot is as follows: 0.45% of Si element, 0.82% of Mg element, 0.25% of Cu element, 0.25% of Zn element, 0.15% of Mn element, 0.04% of Zr element, 0.1% of Cr element, 0.03% of Ti element, 0.25% of Fe element, and the balance is aluminum element.

[0048] The 3003 alloy ingot is successively slit and subjected to the first hot rolling treatment to obtain a first hot rolled sheet with a thickness of 90 mm and a third hot rolled sheet with a thickness of 66 mm. The above-mentioned 6XXX series alloy ingot is milled to obtain a second cast sheet with a thickness of 410 mm. The 4045 alloy ingot is subjected to the third hot rolling treatment to obtain a fourth hot rolled sheet with a thickness of 49 mm. Subsequently, surface cleaning is carried out. The first hot rolled sheet, the second cast sheet, the third hot rolled sheet, and the fourth hot rolled sheet are successively stacked, and the edges are fixed by argon arc welding. Then, it is hot rolled to 6.0 mm at 480 °C, and then cold rolled to a cold rolled sheet with a thickness specification of 1.2 mm. After the cold rolled sheet is annealed at 380 °C for 6 h, it is then brazed at 620 °C for 20 min. After cooling and temperature reduction, it is solution treated at 220 °C for 40 min to obtain an aluminum alloy multi-layer composite sheet, as Figure 1 shown, including a first layer 1, a second layer 2, a third layer 3, and a fourth layer 4 stacked in sequence.

[0049] Example 2

[0050] The difference from Example 1 is that the content of Si element is 0.68%, and the content of Mg element is 0.89%, and finally an aluminum alloy multi-layer composite sheet is obtained.

[0051] Example 3

[0052] The difference from Example 1 is that the content of Si element is 0.31%, and the content of Mg element is 0.62%, and finally an aluminum alloy multi-layer composite sheet is obtained.

[0053] Example 4

[0054] The difference from Example 1 is that the content of Cu element is 0.15%, and the content of Zn element is 0.15%, and finally an aluminum alloy multi-layer composite sheet is obtained.

[0055] Example 5

[0056] The difference from Example 1 is that the content of Mn element is 0.02%, the content of Zr element is 0.08%, and the content of Cr element is 0.01%, and finally an aluminum alloy multi-layer composite sheet is obtained.

[0057] Example 6

[0058] The difference from Example 1 is that the content of Si element is 0.7%, the content of Mg element is 0.9%, and finally an aluminum alloy multi-layer composite plate is obtained.

[0059] Example 7

[0060] The difference from Example 1 is that the content of Cu element is 0.15%, the content of Zn element is 0.25%, and finally an aluminum alloy multi-layer composite plate is obtained.

[0061] Example 8

[0062] The difference from Example 1 is that the content of Mn element is 0.02%, the content of Zr element is 0.08%, and the content of Cr element is 0.1%, and finally an aluminum alloy multi-layer composite plate is obtained.

[0063] Example 9

[0064] The difference from Example 1 is that the content of Ti element is 0.03%, the content of Fe element is 0.6%, and finally an aluminum alloy multi-layer composite plate is obtained.

[0065] Example 10

[0066] The difference from Example 1 is that the thickness of the first hot-rolled plate is 100 mm, the thickness of the second cast plate is 400 mm, the thickness of the third hot-rolled plate is 76 mm, and the thickness of the fourth hot-rolled plate is 39 mm, and finally an aluminum alloy multi-layer composite plate is obtained.

[0067] Example 11

[0068] The difference from Example 1 is that the thickness of the first hot-rolled plate is 110 mm, the thickness of the second cast plate is 390 mm, the thickness of the third hot-rolled plate is 86 mm, and the thickness of the fourth hot-rolled plate is 29 mm, and finally an aluminum alloy multi-layer composite plate is obtained.

[0069] Example 12

[0070] The difference from Example 1 is that the annealing temperature is 440 °C and the annealing holding time is 4 h, and finally an aluminum alloy multi-layer composite plate is obtained.

[0071] Example 13

[0072] The difference from Example 1 is that the annealing temperature is 450 °C and the annealing holding time is 3 h, and finally an aluminum alloy multi-layer composite plate is obtained.

[0073] Example 14

[0074] The difference from Example 1 is that the temperature of the brazing treatment is 600 °C, the holding time is 60 min, the temperature of the aging treatment is 240 °C, and the holding time of the aging treatment is 20 min, and finally an aluminum alloy multi-layer composite plate is obtained.

[0075] Example 15

[0076] The difference from Example 1 is that the temperature of the brazing treatment is 550 °C, the holding time is 90 min, the temperature of the aging treatment is 150 °C, and the holding time of the aging treatment is 50 min, and finally an aluminum alloy multi-layer composite plate is obtained.

[0077] Comparative Example 1

[0078] The difference from Example 1 is that the annealing treatment, brazing treatment and aging treatment are cancelled, and the plate after cold rolling treatment is directly used as the aluminum alloy multi-layer composite plate.

[0079] Comparative Example 2

[0080] The difference from Example 1 is that the content of Si element is 0.85% and the content of Mg element is 0.65%, and finally an aluminum alloy multi-layer composite plate is obtained.

[0081] Comparative Example 3

[0082] The difference from Example 1 is that the addition of Mn element, Zr element and Cr element in the 6XXX series alloy ingot is cancelled, and finally an aluminum alloy multi-layer composite plate is obtained.

[0083] Comparative Example 4

[0084] The difference from Example 1 is that the addition of Cu element and Zn element in the 6XXX series alloy ingot is cancelled, and finally an aluminum alloy multi-layer composite plate is obtained.

[0085] The aluminum alloy multi-layer composite plates prepared in the examples and comparative examples were tested for average grain size, yield strength, tensile strength and elongation, and the stamping situation and overburn of the aluminum alloy multi-layer composite plates were observed. The test results are shown in Table 1.

[0086] Table 1

[0087]

[0088] Figure 2 This is the metallographic structure diagram of the aluminum alloy multi-layer composite plate in Example 1 of this application. It can be seen from Figure 2 that the distribution of the metallographic structure is relatively uniform.

[0089] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0090] In this application, the 6XXX series aluminum alloy is disposed between the 3XXX series aluminum alloys, which helps prevent the high-temperature volatilization of the Mg element in the 6XXX series aluminum alloy, thereby contributing to improving the high-temperature resistance of the multi-layer composite aluminum alloy plate. Moreover, the 3XXX series aluminum alloy has high corrosion resistance. Disposing the 6XXX series aluminum alloy between the 3XXX series aluminum alloys helps improve the corrosion resistance of the multi-layer composite aluminum alloy plate. The function of the 4XXX series aluminum alloy enables the multi-layer composite aluminum alloy plate to be brazed and connected to other aluminum alloy plates. Controlling the contents of the Mg element and the Si element in the 6XXX series aluminum alloy within the above ranges and controlling the content of the Si element to be lower than that of the Mg element helps promote the formation of strengthening phases by the Mg element and the Si element, thereby contributing to improving the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate. Controlling the contents of the Cu element and the Zn element in the 6XXX series aluminum alloy within the above ranges helps promote the formation of strengthening phases between the Cu element and the Zn element and the aluminum element, thereby contributing to further improving the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate. The presence of the Mn element, the Zr element, and the Cr element helps refine the grains. Controlling the contents of the Mn element, the Zr element, and the Cr element within the above ranges helps cooperate synergistically with other elements in the 6XXX series aluminum alloy, thereby contributing to further refining the grains and further contributing to improving the yield strength, tensile strength, and elongation of the multi-layer composite aluminum alloy plate. In addition, this application may have a relatively high iron content, which helps reduce the production cost of the multi-layer composite aluminum alloy plate. Therefore, the multi-layer composite aluminum alloy plate of this application not only has high yield strength, tensile strength, and elongation but also has a low cost.

[0091] The above are only embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An aluminum alloy multilayer composite plate, characterized in that: The aluminum alloy multilayer composite plate comprises a first layer, a second layer, a third layer and a fourth layer stacked in sequence; wherein the first layer and the third layer are both 3XXX series aluminum alloys, the second layer is 6XXX series aluminum alloys, and the fourth layer is 4XXX series aluminum alloys, In terms of mass percentage, the 6XXX series aluminum alloy includes the following elements: 0.3-0.7% Si, 0.6-0.9% Mg, 0.1-0.3% Cu, 0.05-0.3% Zn, 0.01-0.15% Mn, 0.01-0.08% Zr, 0.001-0.1% Cr, 0.001-0.1%, 0.001-0.04% Ti, 0.05-0.6% Fe, and the Si content is lower than the Mg content, the total content of unavoidable impurities is ≤0.15wt%, the content of a single impurity is lower than 0.05wt%, and the balance is Al; the mass ratio of the Si element to the Mg element is (0.50-0.76):

1.

2. The aluminum alloy multilayer composite plate according to claim 1, characterized in that: The 6XXX series aluminum alloy includes the following elements in percentage by mass: the Si element content is 0.45-0.7%, the Mg element content is 0.8-0.9%, the Cu element content is 0.15-0.25%, the Zn element content is 0.15-0.25%, the Mn element content is 0.02-0.15%, the Zr element content is 0.04-0.08%, the Cr element content is 0.01-0.1%, the Ti element content is 0.03-0.04%, the Fe element content is 0.25-0.6%, and the Si element content is lower than the Mg element content, the total content of inevitable impurities is ≤0.15wt%, the content of a single impurity is lower than 0.05wt%, and the balance is Al element.

3. The aluminum alloy multilayer composite plate according to claim 2, characterized in that: The mass ratio of the Mn element, the Zr element and the Cr element is 1:(0.27-4):(0.5-0.7); And / or, the 3XXX series aluminum alloy is selected from any one or more of 3003 alloy, 3004 alloy and 3105 alloy; And / or, the 4XXX series aluminum alloy is selected from any one or more of 4004 alloy, 4045 alloy, 4047 alloy, 4104 alloy, 4147 alloy and 4343 alloy.

4. The aluminum alloy multilayer composite plate according to any one of claims 1 to 3, characterized in that: The thickness of the aluminum alloy multilayer composite plate is 0.5~2.0mm; and / or the average grain size of the aluminum alloy multilayer composite plate is 80~90μm; and / or the yield strength of the aluminum alloy multilayer composite plate is ≥156MPa; and / or the tensile strength of the aluminum alloy multilayer composite plate is ≥205MPa; and / or the elongation of the aluminum alloy multilayer composite plate is ≥14.3%.

5. A method for preparing the aluminum alloy multi-layer composite plate according to any one of claims 1 to 4, characterized in that: The preparation method comprises: Step S1, sequentially performing slitting and a first hot rolling treatment on a 3XXX series aluminum alloy ingot to obtain a first layer of hot rolled plate and a third layer of hot rolled plate, performing surface milling on a 6XXX series aluminum alloy ingot to obtain a second layer of cast plate, and performing a third hot rolling treatment on a 4XXX series aluminum alloy ingot to obtain a fourth layer of hot rolled plate; Step S2, stacking the first layer of hot-rolled plate, the second layer of cast plate, the third layer of hot-rolled plate and the fourth layer of hot-rolled plate in sequence, and then welding and fixing them, performing a second hot rolling treatment, a cold rolling treatment and an annealing treatment in sequence to obtain the aluminum alloy multilayer composite plate.

6. The preparation method according to claim 5, characterized in that: The thickness ratio of the first layer of hot-rolled plate, the second layer of cast plate, the third layer of hot-rolled plate and the fourth layer of hot-rolled plate is (90-100): (400-410): (66-76): (39-49).

7. The preparation method according to claim 6, characterized in that: The temperature of the second hot rolling treatment is 480-490°C; and / or the thickness of the plate after the second hot rolling treatment is 3.0-6.0 mm; and / or the temperature of the annealing treatment is 380-440°C; and / or the holding time of the annealing treatment is 4-6 hours.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The step S2 also includes sequentially performing brazing treatment and aging treatment on the plate obtained after the annealing treatment to obtain the aluminum alloy multilayer composite plate.

9. The preparation method according to claim 8, characterized in that: The temperature of the brazing treatment is 600-625° C.; and / or, the holding time of the brazing treatment is 20-60 min; and / or, the temperature of the aging treatment is 200-240° C.; and / or, the holding time of the aging treatment is 20-40 min.

10. Use of the aluminum alloy multilayer composite plate according to any one of claims 1 to 4 in a liquid cooling plate.

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