Aluminum alloy composite board and preparation method and application thereof

Abstract

The invention provides an aluminum alloy composite plate and a preparation method and application thereof. The aluminum alloy composite plate comprises a first layer, a second layer and a third layer which are sequentially overlapped, wherein the second layer is a 6XXX series aluminum alloy, and the 6XXX series aluminum alloy is prepared from the following elements in percentage by mass: 0.3 to 0.7 percent of Si element, 0.6 to 0.9 percent of Mg element, 0.1 to 0.3 percent of Cu element, 0.05 to 0.3 percent of Zn element, 0.01 to 0.15 percent of Mn element, 0.01 to 0.08 percent of Zr element, 0.001 to 0.1 percent of Cr element, 0.001 to 0.04 percent of Ti element, 0.05 to 0.6 percent of Fe element and the balance of Al element. The aluminum alloy composite plate has high yield strength, tensile strength and ductility.

Description

Technical Field

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

[0002] During the charging and discharging 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 cruising range and battery safety, the application proportion of liquid cooling plates in the thermal management of new energy vehicle batteries will continue to increase. For example, many new energy vehicle brands such as Tesla and BYD are gradually adopting liquid cooling technology to ensure the stable operation of the battery. In addition, with the rapid development of the energy storage industry, the heat generated during the charging and discharging of the energy storage system needs to be transferred immediately to ensure the safety of the system, which poses higher requirements for the liquid cooling plate.

[0003] The core layer of traditional two-layer or three-layer materials for heat exchange is mainly 3003 or its modified alloy. The composite plate has poor anti-collapse ability during high-temperature brazing and low yield strength, 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. It is necessary to carry out supporting steel structure reinforcement, resulting in a significant increase in the weight of the entire liquid cooling plate product, and the lightweight effect is difficult to meet the industry requirements.

[0004] At present, relevant enterprises in the industry are actively developing 3XXX series / 6XXX series / 3XXX series multi-layer composite plates, but the brazing high-temperature conditions are also very harsh. The 6XXX series alloy of the core material of the multi-layer composite plate is difficult to withstand the high-temperature brazing environment and is prone to overburning. In addition, 3XXX series / 6XXX series / 3XXX series need to be age-hardened, and the air-cooling speed at the end of the brazing production line is limited, resulting in an insignificant age-hardening effect of the 6XXX series alloy. For some successfully developed 3XXX series / 6XXX series / 3XXX series composite plates, although their yield strength has been greatly improved compared with 3XXX series / 4XXX series composite plates, it is still difficult to achieve the supporting and bearing effect on the battery module. Therefore, the market's demand for high-strength 3XXX series / 6XXX series / 3XXX series composite plates with a yield strength above 150 MPa, which can independently support and bear the battery module without steel structure, is very urgent. Summary of the Invention

[0005] The main purpose of the present invention is to provide an aluminum alloy composite plate, a preparation method thereof, and an application thereof, so as to solve the problem of low yield strength of the aluminum alloy composite plate in the prior art.

[0006] To achieve the above object, according to one aspect of the present invention, there is provided an aluminum alloy composite plate, which includes a first layer, a second layer and a third layer stacked in sequence; wherein, both the first layer and the third layer are 3XXX series aluminum alloys, and the second layer is a 6XXX 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.

[0007] Further, by mass percentage, the above 6XXX series aluminum alloy includes the following elements: the content of Si element is 0.3 - 0.6%, the content of Mg element is 0.7 - 0.9%, the content of Cu element is 0.2 - 0.3%, the content of Zn element is 0.2 - 0.3%, the content of Mn element is 0.01 - 0.15%, the content of Zr element is 0.01 - 0.05%, the content of Cr element is 0.001 - 0.05%, the content of Ti element is 0.02 - 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.

[0008] Further, the mass ratio of the above Si element to the Mg element is (0.33 - 0.67):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, Zr element and Cr element is 1:(0.07 - 4):(0.007 - 4); and / or, the 3XXX series aluminum alloy is selected from any one or more of 3003 alloy, 3004 alloy and 3105 alloy.

[0009] Further, the thickness of the above aluminum alloy composite plate is 0.5 - 3.0mm; and / or, the average grain size of the aluminum alloy composite plate is 70 - 100μm; and / or, the yield strength of the aluminum alloy composite plate ≥ 165MPa; and / or, the tensile strength of the aluminum alloy composite plate ≥ 215MPa; and / or, the elongation of the aluminum alloy composite plate ≥ 13.0%.

[0010] According to another aspect of the present invention, there is provided a method for preparing the aforementioned aluminum alloy composite plate, and the preparation method includes: Step S1, sequentially performing slitting and first hot rolling treatment on the 3XXX series aluminum alloy ingot to obtain a first hot-rolled plate and a third hot-rolled plate, and performing milling on the 6XXX series aluminum alloy ingot to obtain a second casting plate; Step S2, sequentially stacking the first hot-rolled plate, the second casting plate, and the third hot-rolled plate, and then sequentially performing welding fixation, second hot rolling treatment, and cold rolling treatment to obtain the aluminum alloy composite plate.

[0011] Further, the thickness ratio of the first hot-rolled plate, the second casting plate, and the third hot-rolled plate is (101 - 106):(400 - 410):(62 - 67).

[0012] Further, 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.

[0013] Further, Step S2 further includes sequentially performing annealing treatment, brazing treatment, and aging treatment on the plate obtained after the cold rolling treatment to obtain the aluminum alloy composite plate.

[0014] Further, the temperature of the annealing treatment is 320 - 420 °C; and / or, the holding time of the annealing treatment is 2 - 8 h; and / or, 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.

[0015] According to yet another aspect of the present invention, there is provided the application of the aforementioned aluminum alloy composite plate in a liquid cooling plate.

[0016] Applying the technical solution of the present invention, this application disposes the 6XXX series aluminum alloy between the 3XXX series aluminum alloys, which 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 composite plate. And the 3XXX series aluminum alloy has high corrosion resistance. Disposing the 6XXX series aluminum alloy between the 3XXX series aluminum alloys helps to improve the corrosion resistance of the aluminum alloy composite plate. 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 to promote the formation of strengthening phases by the Mg element and the Si element, thereby helping to improve the yield strength, tensile strength and elongation of the aluminum alloy composite plate. Controlling the contents of the Cu element and the Zn element in the 6XXX series aluminum alloy within the above ranges helps to promote the formation of strengthening phases between the Cu element and the Zn element and the aluminum element, thereby helping to further improve the yield strength, tensile strength and elongation of the aluminum alloy composite plate. The presence of the Mn element, the Zr element and the Cr element helps to refine the grains. Controlling the contents of the Mn element, the Zr element and the Cr element within the above ranges helps to cooperate synergistically with other elements in the 6XXX series aluminum alloy, thereby helping to further refine the grains, and further helping to improve the yield strength, tensile strength and elongation of the aluminum alloy composite plate. In addition, this application can have a relatively high iron content, which helps to reduce the production cost of the aluminum alloy composite plate. Therefore, the aluminum alloy 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

[0017] 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 of the present invention. In the drawings:

[0018] Figure 1 shows a schematic structural diagram of the aluminum alloy composite plate in Embodiment 1 of this application;

[0019] Figure 2 shows a grain structure diagram of the aluminum alloy composite plate in Embodiment 1 of this application;

[0020] Figure 3 shows an overburn diagram of the structure of the aluminum alloy composite plate in Comparative Example 2 of this application;

[0021] Figure 4 shows a grain structure diagram of the aluminum alloy composite plate in Comparative Example 4 of this application;

[0022] Figure 5 shows a schematic structural diagram of the liquid cooling plate of this application.

[0023] Among them, the above-mentioned drawings include the following reference numerals:

[0024] 1. First layer; 2. Second layer; 3. Third layer; 4. Cover plate; 5. Brazing plate. Specific implementation manner

[0025] It should be noted that, without conflict, the embodiments in the present 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.

[0026] As analyzed in the background art of the present application, there is a problem of relatively low yield strength in the existing aluminum alloy composite plate. To solve the above problems, the present application provides an aluminum alloy composite plate, its preparation method and application.

[0027] In a typical implementation manner of the present application, an aluminum alloy composite plate is provided. As Figure 1 shown, the aluminum alloy composite plate includes a first layer 1, a second layer 2 and a third layer 3 stacked in sequence; wherein, both the first layer and the third layer are 3XXX series aluminum alloys, and the second layer is a 6XXX 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.

[0028] 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 aluminum alloy composite 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 aluminum alloy composite plate. 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 aluminum alloy composite 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 aluminum alloy composite 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 aluminum alloy composite plate. In addition, this application can have a relatively high iron content, which helps reduce the production cost of the aluminum alloy composite plate. Therefore, the aluminum alloy composite plate of this application not only has high yield strength, tensile strength, and elongation, but also has a low cost.

[0029] In order to further improve the yield strength, tensile strength, and elongation of the aluminum alloy composite 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 0.3 - 0.6%, the content of the Mg element is 0.7 - 0.9%, the content of the Cu element is 0.2 - 0.3%, the content of the Zn element is 0.2 - 0.3%, the content of the Mn element is 0.01 - 0.15%, the content of the Zr element is 0.01 - 0.05%, the content of the Cr element is 0.001 - 0.05%, the content of the Ti element is 0.02 - 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.

[0030] In an embodiment of the present application, the mass ratio of the above Si element to the Mg element is (0.33~0.67):1, specifically, it can be 0.33:1, 0.40:1, 0.45:1, 0.50:1, 0.55:1, 0.60:1, 0.67:1, 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:(0.07~4):(0.007~4); and / or, the 3XXX series aluminum alloy is selected from any one or more of 3003 alloy, 3004 alloy, and 3105 alloy, and preferably the 3XXX series aluminum alloy is 3003 alloy.

[0031] 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 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, the Zn element, and the aluminum element, and further helping to further improve the yield strength, tensile strength, and elongation of the aluminum alloy 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 composite plate.

[0032] In an embodiment of the present application, the mass ratio of the above Ti element to the Fe element is (11~14):1, specifically, it can be 11:1, 11.5:1, 12:1, 12.5:1, 13:1, 13.5:1, 14:1, and the range values between any two ratios.

[0033] The presence of the Ti element helps to stabilize the precipitated phases in the material, reduce the aggregation of the precipitated phases during the aging treatment process, and helps to improve their uniform distribution. The presence of the Fe element helps to promote the stability of these precipitated phases and further improve the strength and hardness of the material. Controlling the mass ratio of the Ti element to the Fe element within the above range helps to optimize the distribution of the precipitation strengthening phases, thereby helping to further improve the yield strength, tensile strength, and elongation of the aluminum alloy composite plate.

[0034] In an embodiment of the present application, the thickness of the above aluminum alloy composite plate is 0.5 - 3.0 mm; and / or, the average grain size of the aluminum alloy composite plate is 70 - 100 μm; and / or, the yield strength of the aluminum alloy composite plate is ≥165 MPa; and / or, the tensile strength of the aluminum alloy composite plate is ≥215 MPa; and / or, the elongation of the aluminum alloy composite plate is ≥13.0%; preferably, the yield strength of the aluminum alloy composite plate is 175 - 185 MPa; and / or, the tensile strength of the aluminum alloy composite plate is 224 - 241 MPa; and / or, the elongation of the aluminum alloy composite plate is 14.0 - 16.5%.

[0035] Controlling the average grain size of the aluminum alloy composite plate within the above range helps to further improve the yield strength, tensile strength, and elongation of the aluminum alloy composite plate. The aluminum alloy composite plate with the above yield strength, tensile strength, and elongation is more suitable for liquid cooling plates.

[0036] In another typical embodiment of the present application, a method for preparing the above aluminum alloy composite plate is provided. The preparation method includes: Step S1, successively cutting and performing the first hot rolling treatment on the 3XXX series aluminum alloy ingot to obtain the first hot rolled plate and the third hot rolled plate, and milling the 6XXX series aluminum alloy ingot to obtain the second cast plate; Step S2, successively stacking the first hot rolled plate, the second cast plate, and the third hot rolled plate, and then successively performing welding fixation, the second hot rolling treatment, and cold rolling treatment to obtain the aluminum alloy composite plate.

[0037] In Step S1, the 3XXX series aluminum alloy ingot and the 6XXX series aluminum alloy ingot are pretreated to obtain the first hot rolled plate, the second cast plate, and the third hot rolled plate with appropriate specifications. In Step S2, successively stacking the first hot rolled plate, the second cast plate, and the third hot rolled plate and then performing welding fixation helps to tightly combine the first hot rolled plate, the second cast plate, and the third hot rolled plate together to form 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 forming a microstructure that improves the strength and ductility of the material. The cold rolling treatment helps to precisely control the thickness of the aluminum alloy composite plate and at the same time improve the surface finish of the aluminum alloy composite plate.

[0038] In an embodiment of the present application, the thickness ratio of the above first hot rolled plate, second cast plate, and third hot rolled plate is (101 - 106):(400 - 410):(62 - 67).

[0039] The presence of the first hot-rolled plate and the third hot-rolled plate helps to improve the corrosion resistance and high-temperature stability of the aluminum alloy composite plate. The presence of the second cast plate helps to improve the yield strength, tensile strength, and elongation of the aluminum alloy composite plate. Controlling the thickness ratio of the first hot-rolled plate, the second cast plate, and the third hot-rolled plate within the above range helps to enhance the mutual synergy among them, thereby contributing to improving the comprehensive performance of the aluminum alloy composite plate and making it more suitable for liquid cooling plates.

[0040] In an embodiment of the present application, 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.

[0041] Controlling the temperature of the second hot rolling treatment within the above range helps to promote the refinement and homogenization of internal grains, thereby contributing to improving the yield strength, tensile strength, and elongation of the aluminum alloy composite plate. Controlling the thickness of the plate after the second hot rolling treatment within the above range helps to control the thickness of the finally formed aluminum alloy composite plate.

[0042] In an embodiment of the present application, the above step S2 further includes successively annealing, brazing, and aging the plate obtained after cold rolling to obtain an aluminum alloy composite plate.

[0043] The purpose of the annealing treatment is to eliminate the work hardening generated during cold rolling and restore the plasticity of the material. The brazing treatment helps to form a firm metallurgical bond between the layers of the composite plate, enhancing the overall structural strength of the composite plate so that it can bear the weight of the battery module without additional steel bracket reinforcement. The role of the aging treatment is to further improve the yield strength and tensile strength of the composite plate through the precipitation strengthening mechanism while maintaining sufficient elongation. Preferably, the above brazing treatment is carried out in a brazing chain furnace. The above annealing treatment is carried out in a box furnace or a cushion furnace.

[0044] In an embodiment of the present application, the temperature of the annealing treatment is 320 - 420 °C; and / or, the holding time of the annealing treatment is 2 - 8 h; and / or, 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.

[0045] Controlling the temperature and time of the annealing treatment within the above ranges helps to eliminate the work hardening of the composite plate after cold rolling, while reducing the overheating decomposition of alloy elements and maintaining the original composition of the material. Controlling the temperature and time of the brazing treatment within the above ranges helps to improve the interaction between layers and, at the same time, helps to reduce the risk of overburning of the aluminum alloy composite plate. Controlling the temperature and time of the aging treatment within the above ranges helps to optimize the microstructure of the composite plate, thereby helping to improve the yield strength, tensile strength, and elongation of the aluminum alloy composite plate.

[0046] In another typical embodiment of the present application, an application of the aforementioned aluminum alloy composite plate on a liquid cooling plate is provided.

[0047] The aluminum alloy 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 5 The shown liquid cooling plate includes a cover plate 4 and a brazing plate 5, and the cover plate 4 is the aluminum alloy composite plate of the present application.

[0048] The beneficial effects of the present application will be further described below in conjunction with embodiments.

[0049] Example 1

[0050] Element ratio of the 6XXX series alloy ingot by mass percentage: 0.4% Si element, 0.7% Mg element, 0.2% Cu element, 0.2% Zn element, 0.1% Mn element, 0.05% Zr element, 0.05% Cr element, 0.02% Ti element, 0.25% Fe element, and the balance is aluminum element.

[0051] The 3003 alloy ingot is successively slit and subjected to the first hot rolling treatment to obtain a first hot rolled plate with a thickness of 101 mm and a third hot rolled plate with a thickness of 62 mm. The above 6XXX series alloy ingot is milled to obtain a second casting plate with a thickness of 410 mm, and then surface cleaned. The first hot rolled plate, the second casting plate, and the third hot rolled plate are successively stacked, fixed by argon arc welding at the edges, and then subjected to the second hot rolling treatment at 490 °C until it is hot rolled to 6.0 mm, followed by cold rolling treatment. Finally, a cold rolled plate with a thickness specification of 1.5 mm is obtained. The cold rolled plate is subjected to an annealing treatment at a temperature of 380 °C for 3 h. The annealed plate is subjected to a brazing treatment at 620 °C for 40 min, and then the cooled plate is subjected to an aging treatment at 240 °C for 40 min to obtain an aluminum alloy composite plate, as Figure 1 shown, including a first layer 1, a second layer 2, and a third layer 3 stacked in sequence.

[0052] Example 2

[0053] The difference from Example 1 is that the content of Si element is 0.3%, the content of Mg element is 0.6%, and finally an aluminum alloy composite plate is obtained.

[0054] Example 3

[0055] The difference from Example 1 is that the content of Si element is 0.3%, the content of Mg element is 0.9%, and finally an aluminum alloy composite plate is obtained.

[0056] Example 4

[0057] The difference from Example 1 is that the content of Si element is 0.6%, the content of Mg element is 0.9%, and finally an aluminum alloy composite plate is obtained.

[0058] Example 5

[0059] The difference from Example 1 is that the content of Si element is 0.5%, the content of Mg element is 0.9%, and finally an aluminum alloy composite plate is obtained.

[0060] Example 6

[0061] The difference from Example 1 is that the content of Si element is 0.5%, the content of Mg element is 0.8%, and finally an aluminum alloy composite plate is obtained.

[0062] Example 7

[0063] The difference from Example 1 is that the content of Cu element is 0.1%, the content of Zn element is 0.05%, and finally an aluminum alloy composite plate is obtained.

[0064] Example 8

[0065] The difference from Example 1 is that the content of Cu element is 0.1%, the content of Zn element is 0.1%, and finally an aluminum alloy composite plate is obtained.

[0066] Example 9

[0067] The difference from Example 1 is that the content of Cu element is 0.3%, the content of Zn element is 0.3%, and finally an aluminum alloy composite plate is obtained.

[0068] Example 10

[0069] The difference from Example 1 is that the content of Mn element is 0.1%, the content of Zr element is 0.01%, and the content of Cr element is 0.08%, and finally an aluminum alloy composite plate is obtained.

[0070] Example 11

[0071] The difference from Example 1 is that the content of Mn element is 0.01%, the content of Zr element is 0.04%, and the content of Cr element is 0.04%, and finally an aluminum alloy composite plate is obtained.

[0072] Example 12

[0073] The difference from Example 1 is that the content of Mn element is 0.15%, the content of Zr element is 0.01%, and the content of Cr element is 0.001%, and finally an aluminum alloy composite plate is obtained.

[0074] Example 13

[0075] 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 used as the aluminum alloy composite plate.

[0076] Example 14

[0077] The difference from Example 1 is that the content of Si element is 0.6% and the content of Mg element is 0.8%, and finally an aluminum alloy composite plate is obtained.

[0078] Example 15

[0079] The difference from Example 1 is that the content of Cu element is 0.2% and the content of Zn element is 0.3%, and finally an aluminum alloy composite plate is obtained.

[0080] Example 16

[0081] The difference from Example 1 is that the content of Mn element is 0.01%, the content of Zr element is 0.05%, and the content of Cr element is 0.05%, and finally an aluminum alloy composite plate is obtained.

[0082] Example 17

[0083] 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 200 °C, and the holding time of the aging treatment is 20 min, and finally an aluminum alloy composite plate is obtained.

[0084] Example 18

[0085] 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 composite plate is obtained.

[0086] Example 19

[0087] The difference from Example 1 is that the thickness of the first-layer hot-rolled plate is 106 mm, the thickness of the second-layer cast plate is 400 mm, and the thickness of the third-layer hot-rolled plate is 67 mm, and finally an aluminum alloy composite plate is obtained.

[0088] Example 20

[0089] The difference from Example 1 is that the thickness of the first-layer hot-rolled plate is 110 mm, the thickness of the second-layer cast plate is 393 mm, and the thickness of the third-layer hot-rolled plate is 70 mm, and finally an aluminum alloy composite plate is obtained.

[0090] Comparative Example 1

[0091] The difference from Example 1 is that the content of Si element is 0.2% and the content of Mg element is 0.4%, and finally an aluminum alloy composite plate is obtained.

[0092] Comparative Example 2

[0093] The difference from Example 1 is that the content of Si element is 0.8% and the content of Mg element is 0.5%, and finally an aluminum alloy composite plate is obtained.

[0094] Comparative Example 3

[0095] 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 composite plate is obtained.

[0096] Comparative Example 4

[0097] 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 composite plate is obtained.

[0098] The aluminum alloy composite plates prepared in the examples and comparative examples were tested for average grain size, yield strength, tensile strength and elongation, and whether the aluminum alloy composite plates were overburned was observed. The test results are shown in Table 1.

[0099] Table 1

[0100]

[0101] Figure 2 This is the grain structure diagram of the aluminum alloy composite plate in Example 1 of the present application. From Figure 2 it can be measured that the average grain size is 80 μm.

[0102] Figure 3 This shows the overburn diagram of the aluminum alloy composite plate in Comparative Example 2 of the present application. From Figure 3 it can be seen that the structure shows an overburn phenomenon.

[0103] Figure 4Shows the grain structure diagram of the aluminum alloy composite plate in Comparative Example 4 of the present application. From Figure 4 it can be measured that the average size of the grains is 197 μm.

[0104] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0105] In the present application, the 6XXX series aluminum alloy is disposed between the 3XXX series aluminum alloys, which 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 composite plate. And the 3XXX series aluminum alloy has high corrosion resistance. Disposing the 6XXX series aluminum alloy between the 3XXX series aluminum alloys helps to improve the corrosion resistance of the aluminum alloy composite plate. 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 the content of the Mg element, helps to promote the formation of strengthening phases by the Mg element and the Si element, thereby helping to improve the yield strength, tensile strength and elongation of the aluminum alloy composite plate. Controlling the contents of the Cu element and the Zn element in the 6XXX series aluminum alloy within the above ranges helps to promote the formation of strengthening phases between the Cu element and the Zn element and the aluminum element, thereby helping to further improve the yield strength, tensile strength and elongation of the aluminum alloy composite plate. The presence of the Mn element, Zr element and Cr element helps to refine the grains. Controlling the contents of the Mn element, Zr element and Cr element within the above ranges helps to cooperate synergistically with other elements in the 6XXX series aluminum alloy, thereby helping to further refine the grains, and further helping to improve the yield strength, tensile strength and elongation of the aluminum alloy composite plate. In addition, the present application can have a relatively high iron content, thereby helping to reduce the production cost of the aluminum alloy composite plate. Therefore, the aluminum alloy composite plate of the present application not only has high yield strength, tensile strength and elongation, but also has a low cost.

[0106] The above are only the 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 composite plate, characterized in that, The aluminum alloy composite plate comprises a first layer, a second layer and a third layer stacked in sequence; wherein, both the first layer and the third layer are 3XXX series aluminum alloys, and the second layer is a 6XXX series aluminum alloy. By mass percentage, the 6XXX series aluminum alloy comprises 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.

2. The aluminum alloy composite plate according to claim 1, characterized in that, By mass percentage, the 6XXX series aluminum alloy comprises the following elements: the content of Si element is 0.3 - 0.6%, the content of Mg element is 0.7 - 0.9%, the content of Cu element is 0.2 - 0.3%, the content of Zn element is 0.2 - 0.3%, the content of Mn element is 0.01 - 0.15%, the content of Zr element is 0.01 - 0.05%, the content of Cr element is 0.001 - 0.05%, the content of Ti element is 0.02 - 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.

3. The aluminum alloy composite plate according to claim 2, characterized in that, The mass ratio of the Si element to the Mg element is (0.33 - 0.67):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:(0.07 - 4):(0.007 - 4); and / or, the 3XXX series aluminum alloy is selected from any one or more of 3003 alloy, 3004 alloy and 3105 alloy.

4. The aluminum alloy composite plate according to any one of claims 1 to 3, characterized in that, The thickness of the aluminum alloy composite plate is 0.5 - 3.0mm; and / or, the average grain size of the aluminum alloy composite plate is 70 - 100μm; and / or, the yield strength of the aluminum alloy composite plate ≥ 165MPa; and / or, the tensile strength of the aluminum alloy composite plate ≥ 215MPa; and / or, the elongation of the aluminum alloy composite plate ≥ 13.0%.

5. A method for preparing the aluminum alloy composite plate according to any one of claims 1 to 4, characterized in that, The preparation method comprises: Step S1, sequentially cutting and performing a first hot rolling treatment on a 3XXX series aluminum alloy ingot to obtain a first layer hot rolled plate and a third layer hot rolled plate, and milling a 6XXX series aluminum alloy ingot to obtain a second layer casting plate. Step S2: Stack the first hot-rolled plate, the second cast plate, and the third hot-rolled plate in sequence, and then perform welding fixation, second hot-rolling treatment, and cold-rolling treatment in sequence to obtain the aluminum alloy composite plate.

6. The preparation method according to claim 5, wherein, The thickness ratio of the first hot-rolled plate, the second cast plate, and the third hot-rolled plate is (101~106):(400~410):(62~67).

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.

8. The preparation method according to any one of claims 5 to 7, characterized in that, Step S2 further includes annealing treatment, brazing treatment, and aging treatment on the plate obtained after the cold-rolling treatment in sequence to obtain the aluminum alloy composite plate.

9. The preparation method according to claim 8, wherein, The temperature of the annealing treatment is 320~420 °C; and / or, the holding time of the annealing treatment is 2~8 h; and / or, 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. Application of the aluminum alloy composite plate according to any one of claims 1 to 4 to a liquid cooling plate.

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