Core material, high-strength aluminum alloy composite board containing core material and preparation method and brazing method of high-strength aluminum alloy composite board

Abstract

The invention provides a core material, a high-strength aluminum alloy composite board containing the core material and a preparation method and a brazing method of the high-strength aluminum alloy composite board, and the rapid aging aluminum alloy core material comprises the following alloy components of, by mass, 0.3%-0.8% of Si, 0.6%-2.0% of Mn, 0.4%-1.5% of Mg, 1.2%-2.4% of Cu, smaller than or equal to 1.7% of Fe and the balance Al. The total number density of dispersed phases in the rapid aging aluminum alloy core material is larger than or equal to 5.4 * 10 < 5 > / mm < 2 >, and the proportion of P textures in the rapid aging aluminum alloy core material is 10% or above. The strength of the aluminum alloy composite board can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum alloys, and in particular to a core material, a high-strength aluminum alloy composite plate containing the core material, and a preparation method and a brazing method thereof, and particularly to a rapid aging aluminum alloy core material, a high-strength aluminum alloy composite plate containing the core material, and a preparation method and a brazing method thereof. Background Art

[0002] Electric vehicles, as a key new energy vehicle, have experienced rapid growth. However, electric vehicle batteries generate significant heat during high-load operation or rapid charging. If this heat is not dissipated promptly, it can severely impact battery performance and lifespan, and may even pose safety risks. Therefore, efficient thermal management systems have become an integral part of electric vehicle design. Aluminum alloy, due to its excellent thermal conductivity, corrosion resistance, lightweight construction, and excellent processability, is an ideal material for battery cooling plates.

[0003] The water-cooling plates currently on the market are mainly made of 3xxx and 6xxx series aluminum alloys. The strength of 3xxx water-cooling plates can no longer meet market demand. 6xxx aluminum alloys can greatly improve material strength through artificial aging treatment after welding, and have gradually become the mainstream water-cooling plate material on the market. Compared with artificial aging treatment, natural aging only requires the sample to be placed at room temperature for a period of time to achieve a strengthening effect. Therefore, naturally aging-strengthened aluminum alloy water-cooling plates better meet low-carbon and environmental protection needs, and are gradually replacing artificial aging-strengthened water-cooling plates to become the mainstream type of water-cooling plates on the market. In addition, the market has also begun to pay attention to the carbon emissions of water-cooling plates, and the demand for water-cooling plates that can consume waste and reduce carbon emissions has also gradually increased in the market.

[0004] Currently, new alloys that combine 3XXX (solid solution strengthening of Mn and dispersion strengthening of Mn-containing dispersed phases) and 6XXX (aging strengthening of Mg2Si) have appeared on the market. For example, CN116875864B discloses a naturally aged water-cooled plate material containing 0.2-0.7 wt% Si, 0.95-1.45 wt% Cu, 0.3-0.9 wt% Mg, 0.6-1.6 wt% Mn, 0.2 wt% or more Fe, and the balance Al and unavoidable impurities. The ratio of Mg to Si is ≥1.0, and the ratio of the total Fe and Mn content to Si is ≥2.0. The composite plate exhibits a yield strength of ≥100 MPa and an elongation of ≥15% after two weeks of natural aging.

[0005] However, in the new energy field, in order to achieve thinning and lightweighting, the strength requirements for water-cooled plates after natural aging are gradually increasing, and it is hoped that the strength of emerging alloys will be further improved. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a rapid-aging aluminum alloy core material, a high-strength aluminum alloy composite plate containing the same, and a preparation method and a brazing method thereof, and in particular relates to a natural-aging aluminum alloy core material, a high-strength aluminum alloy composite plate containing the same, and a preparation method and a brazing method thereof, so as to improve the strength of the aluminum alloy composite plate.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a rapid aging aluminum alloy core material, comprising the following alloy components by mass percentage: Si: 0.3-0.8%, Mn: 0.6-2.0%, Mg: 0.4-1.5%, Cu: 1.2-2.4%, and Fe ≤ 1.7%. The total number density of AlMnSi series and AlCuMg series dispersed phases in the rapid aging aluminum alloy core material is ≥ 5.4×10 5 Pieces / mm 2 The P texture accounts for more than 10% in the rapid aging aluminum alloy core material.

[0009] For Al-Mn-Mg-Si alloy, the inventors found that by regulating a reasonable soaking process, a large amount of AlMnSi dispersed phase will be produced after soaking.

[0010] If Cu is added to the system, AlCuMg dispersed phases and AlMnSiFeCu dispersed phases will be generated in the soaking stage. By regulating the hot rolling process reasonably, the coarse equiaxed crystals or columnar crystals can be transformed into fibrous structures. In the annealing stage, the AlMnSi series dispersed phases and AlCuMg series dispersed phases hinder recrystallization, which helps to promote the transformation of part of the fibrous structure into P texture.

[0011] Control of each element content:

[0012] The Mn element content is controlled to be 0.6-2.0%.

[0013] The main function of the Mn element is to dissolve into the matrix to achieve solid solution strengthening. Furthermore, it can form submicron-sized AlMnSi and AlMnSiFeCu dispersed phases with Si and other elements, exerting a dispersion strengthening effect. These AlMnSi and AlMnSiFeCu dispersed phases can also hinder recrystallization and refine the grain structure. When the Mn content in an aluminum alloy is less than 0.6%, the solid solution strengthening effect is minimal, and it is difficult to ensure that sufficient submicron-sized AlMnSi(CuMg) dispersed phases precipitate during the subsequent soaking treatment. A Mn content above 2.0% can easily lead to the formation of excessive coarse intermetallic compounds between Mn and Fe and Cu during the casting process. After soaking, a large amount of coarse AlMnFeCu compounds will remain, adversely affecting the mechanical properties of the aluminum alloy.

[0014] The Si element content is controlled to be 0.3-0.8%.

[0015] In the system of the present invention, Si combines with elements such as Mn and Si during soaking to precipitate AlMnSi and AlMnSiFeCu dispersed phases. These phases pin grain boundaries during annealing, promoting the formation of a P texture. Too little Si content is insufficient to achieve this effect, while too much lowers the melting point of the material, increasing the risk of overheating during brazing.

[0016] The Mg element content is controlled to be 0.4-1.5%, and the Cu element content is controlled to be 1.2-2.4%.

[0017] Mg and Cu promote the precipitation of the AlCuMg dispersed phase during homogenization, which facilitates the formation of a P texture during annealing. When the Mg and Cu content is below 0.4%, it is difficult to form a sufficient number of strengthening phases, resulting in a weak strengthening effect. Excessive Mg and Cu content increases the risk of casting cracking and can also cause poor brazing.

[0018] Fe is an impurity element. A high content of Fe easily leads to the formation of coarse compounds in the alloy. Its content is controlled within 1.7%.

[0019] The total number density of the dispersed phase in the rapid aging aluminum alloy core material is ≥5.4×10 5 Pieces / mm 2 The dispersed phases in the aluminum alloy core material include two major types of dispersed phases: the AlMnSi series and the AlCuMg series. The AlMnSi series dispersed phases include the AlMgSi dispersed phase and the AlMnSiFeCu dispersed phase. The AlCuMg series dispersed phases are such as the AlCuMg dispersed phase. When Zr is present, the AlCuMg series dispersed phases also include the AlCuMgZr dispersed phase.

[0020] By controlling the total number density of dispersed phases in the rapid aging aluminum alloy core material to be sufficient, the grain boundaries are pinned during the annealing process, thereby promoting the generation of more P textures. The P texture in the rapid aging aluminum alloy core material accounts for more than 10%.

[0021] Specifically, the Si content in the rapid aging aluminum alloy core material is 0.3-0.8%, such as 0.3%, 0.36%, 0.42%, 0.47%, 0.53%, 0.58%, 0.64%, 0.69%, 0.75% or 0.8%, but is not limited to the values ​​listed, and other values ​​not listed in the range are also applicable; Mn content is 0.6-2.0%, such as 0.6%, 0.8%, 1%, 1.1%, 1.3%, 1.4%, 1.6%, 1.7%, 1.9% or 2.0%, but is not limited to the values ​​listed, and other values ​​not listed in the range are also applicable; Mg content is 0.4-1.5%, such as 0.4%, 0.6%, 0.7%, 0.8%, 1%. .8%, 0.9%, 1.1%, 1.2%, 1.3%, 1.4% or 1.5%, etc., but not limited to the listed values, other values ​​not listed in this range are also applicable; Cu: 1.2-2.4%, for example, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, 1.9%, 2%, 2.2%, 2.3% or 2.4%, etc., but not limited to the listed values, other values ​​not listed in this range are also applicable; Fe ≤ 1.7%, for example, 1.7%, 1.6%, 1.5%, 1.4%, 1.3%, 1.2%, 1.1%, 1%, 0.9% or 0.7%, etc., but not limited to the listed values, other values ​​not listed in this range are also applicable. The total number density of AlMnSi series and AlCuMg series dispersed phases in the rapid aging aluminum alloy core material is ≥5.4×10 5 Pieces / mm 2 , for example, it can be 5.4×10 5 Pieces / mm 2 , 5.5×10 5 Pieces / mm 2 , 5.6×10 5 Pieces / mm 2 , 5.8×10 5 Pieces / mm 2 , 6.0×10 5 Pieces / mm 2 , 6.2×10 5 Pieces / mm 2 , 6.5×10 5 Pieces / mm 2 , 7.0×10 5 Pieces / mm 2 , 7.5×10 5Pieces / mm 2 or 8.0×10 5 Pieces / mm 2 The P texture in the rapid aging aluminum alloy core material accounts for more than 10%, for example, 10%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc., but is not limited to the listed values. Other values ​​not listed within this range are also applicable.

[0022] Preferably, the rapid aging aluminum alloy core material further comprises the following alloy components in terms of mass percentage: Zr: 0.01-0.2%, for example, 0.01%, 0.04%, 0.06%, 0.08%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18% or 0.2%, etc., but is not limited to the listed values, and other values ​​not listed in this range are also applicable. The number density of the AlCuMgZr dispersed phase in the rapid aging aluminum alloy core material is ≥3×10 4 Pieces / mm 2 , for example, it can be 3×10 4 Pieces / mm 2 , 3.2×10 4 Pieces / mm 2 , 3.3×10 4 Pieces / mm 2 , 3.5×10 4 Pieces / mm 2 , 3.8×10 4 Pieces / mm 2 , 3.9×10 4 Pieces / mm 2 , 4.2×10 4 Pieces / mm 2 , 4.5×10 4 Pieces / mm 2 , 5.5×10 4 Pieces / mm 2 , 6.5×10 4 Pieces / mm 2 , 7.0×10 4 Pieces / mm 2 , 7.5×10 4 Pieces / mm 2 or 8.0×10 4 Pieces / mm 2 The above values ​​are not limited to the above values, and other values ​​not listed in the above values ​​are also applicable.

[0023] P texture helps increase the material's yield strength. Experimental studies have found that the AlMnSi disperse phase contributes to the formation of P texture during annealing. However, the proportion of P texture decreases significantly at brazing temperatures, indicating that the AlMnSi phase at brazing temperatures cannot effectively prevent the P texture from transforming into other textures. In other words, in materials containing only the AlMnSi disperse phase, the P texture formed during annealing undergoes a transformation during brazing, resulting in a decrease in its proportion.

[0024] In materials containing both AlMnSi and AlCuMg dispersed phases, when the total amount of dispersed phases is comparable to that of materials containing only AlMnSi dispersed phases, the area ratio of the P texture formed during annealing is essentially the same, and the amount of P texture is significantly reduced after brazing. However, during brazing, the AlCuMg dispersed phase completely dissolves, which is presumably the reason for the reduction in P texture.

[0025] When a certain amount of Zr element is added to the above-mentioned system materials, an AlCuMgZr dispersed phase in addition to the AlMnSi and AlCuMg dispersed phases will be formed during the soaking process, which helps to form the P texture during the annealing process. The difference is that the AlCuMgZr dispersed phase will not disappear during the brazing process and can effectively hinder the change of the P texture. After welding, the P texture ratio can still be retained to the same level as after annealing.

[0026] Furthermore, the inventors discovered that when the total number density of the dispersed phase is similar, the P texture content generated during the annealing stage after the materials undergo the same hot and cold rolling processes is essentially the same. However, when the number density ratio of the AlCuMgZr dispersed phase varies, the P texture content remaining after brazing varies significantly, generally showing the following pattern: the higher the number density ratio of the AlCuMgZr dispersed phase, the greater the amount of P texture retained. This indicates that the AlCuMgZr dispersed phase is beneficial for retaining the P texture during the brazing process.

[0027] Zr: 0.01-0.2%. When added to the system, Zr forms an AlCuMgZr dispersed phase during the soaking stage. This dispersed phase helps form the P texture during annealing and hinders the change of the P texture during brazing. Excessive Zr will form coarse compounds with Ti, which can easily become crack initiation points during deformation, deteriorating the alloy's mechanical properties. It also reduces the heterogeneous nucleation effect of Ti, leading to grain coarsening.

[0028] Preferably, the ratio of the mass content of Mg to the mass content of Si in the rapid aging aluminum alloy core material is greater than 0.7, for example, it can be 0.71, 0.72, 0.73, 0.75, 0.78, 0.79, 0.80, 0.82, 0.83, 0.84, 0.85, 0.88, 0.9, 0.92, 0.95, 0.98, 0.99 or 1, but is not limited to the listed values, and other values ​​not listed within this range are also applicable.

[0029] The inventors found that the AlMnSiFeCu dispersed phase in the AlMnSi series dispersed phases and the AlCuMg series dispersed phases compete with each other during the formation process, and the AlCuMg series dispersed phases, especially the AlCuMgZr dispersed phases, are the dispersed phases that the inventors prefer to form. By controlling Mg / Si>0.7, the higher the Mg element content, the more AlCuMg series dispersed phases are produced.

[0030] Preferably, the Fe content in the rapid aging aluminum alloy core material is 0.1-1.1%, for example, it can be 0.1%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or 1.1%, etc., but is not limited to the listed values. Other values ​​not listed in this range are also applicable, preferably 0.5-1.1%.

[0031] Preferably, in terms of mass percentage, the Si element in the rapid aging aluminum alloy core material is controlled to be 0.5-0.8%.

[0032] In the present invention, the total amount of iron and manganese will affect the elongation. In addition, factors such as the major diameter size of the coarse compounds will also affect the elongation.

[0033] The Fe element can improve the casting formability of the alloy, and the high Fe content in the waste usually leads to an extremely low recovery rate. Increasing the Fe content in the system is conducive to applying a higher waste recovery rate and reducing carbon emissions. However, the increase in the Fe element content easily leads to the production of coarse compounds in the alloy, especially when the system also contains a high content of Mn elements, which easily generates coarse Al6 (FeMn) compounds. The coarse Al6 (FeMn) compounds will not break during the hot rolling process, and are difficult to completely eliminate during the subsequent heat treatment process, which will seriously reduce the strength and elongation of the material. The inventors found that when the system contains the Cu element, it will cause the system to generate AlMnFeCu phase instead of Al6 (FeMn) phase. Although the AlMnFeCu phase is relatively hard and still constitutes a coarse compound that is difficult to break, it was found that during the homogenization heat treatment process, if there is sufficient Si element to diffuse into the coarse blocky and strip-shaped AlMnFeCu eutectic phase in the alloy, the harder AlMnFeCu phase can be transformed into the relatively soft AlMnFeSiCu phase and α-Al, and the AlMnFeSiCu phase can be broken during the subsequent rolling process.

[0034] The Si element is controlled to be 0.5-0.8%. When the Si element is too little, the AlMnFeSiCu phase and the AlMnSi dispersed phase form a competitive relationship, and the Si element is relatively insufficient to promote the transformation of the AlMnFeCu phase into the AlMnSiFeCu phase and α-Al.

[0035] Preferably, the rapid aging aluminum alloy core material does not contain coarse compounds, wherein the coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm.

[0036] The inventors discovered that controlling the Si and Cu element contents and subsequent heat treatment processes can help promote the transformation of coarse compounds. The coarse compounds produced in the present invention are generally AlMnFeCu eutectic phases, wherein the Cu element can change the lattice constant of the AlMnFeSiCu compound, which helps to promote the diffusion of Si elements into the AlMnFeCu coarse compound by regulating a specific soaking process, forming AlMnSiFeCu phases and α-Al. The AlMnFeSiCu phase is a relatively soft compound that can be broken during hot rolling and cold rolling, thereby achieving the effect of refining the coarse compounds. In addition, during the brazing process, the AlMnSiFeCu phase that is broken by rolling and the AlMnFeCu phase that has not been transformed will both mature, which can ensure that the material still has a high elongation after welding.

[0037] Preferably, the rapid aging aluminum alloy core material further contains Ti element.

[0038] Ti is a common alloying element that is suitable for helping to refine the grains of the aluminum alloy matrix. Further adding Ti to the core material can help improve the strength of the material.

[0039] In a second aspect, the present invention provides a high-strength aluminum alloy composite plate material, comprising a core material layer and a barrier layer arranged on one side and / or both sides of the surface of the core material layer, wherein the core material layer is the rapid aging aluminum alloy core material described in the first aspect.

[0040] Preferably, the barrier layer comprises a first barrier layer and a second barrier layer provided on both sides of the surface of the rapid aging aluminum alloy core material.

[0041] Preferably, the barrier layer comprises the following alloy components by weight: Cu: 0.5-2.0%, Mg ≤ 0.05%. The Cu content may be, for example, 0.5%, 0.7%, 0.9%, 1%, 1.2%, 1.4%, 1.5%, 1.7%, 1.9%, or 2.0%, but is not limited to the values ​​listed above. Other values ​​not listed within this range are also applicable. The Mg content may be, for example, 0.05%, 0.048%, 0.045%, 0.042%, 0.040%, 0.039%, 0.035%, 0.032%, 0.03%, 0.028%, 0.025%, 0.02%, 0.019%, 0.015%, or 0.01%, but is not limited to the values ​​listed above. Other values ​​not listed within this range are also applicable.

[0042] Preferably, the barrier layer further contains Zr in weight percentage: 0.1-1wt%, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt% or 1wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0043] Preferably, the barrier layer further contains Ti in a weight percentage of 0-0.1 wt%, for example, it can be 0, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt% or 0.1 wt%, etc., but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0044] The medium-high strength, rapid aging aluminum alloy composite sheet of the present invention can be used in brazing with materials containing a brazing layer. The main function of the barrier layer is to prevent the diffusion of Mg from the core material layer to the brazing layer during the brazing process, thereby avoiding the harmful effects caused by the reaction of Mg with the brazing flux.

[0045] The Cu element in this barrier layer has the following main functions: First, the Cu element in the barrier layer prevents the diffusion of excess Cu in the core material into the barrier layer, which can reduce the loss of core material strength after welding. Secondly, when the Cu content in the barrier layer is higher than the Cu content in the core material, the Cu element in the barrier layer can diffuse into the core material, thereby improving the core material performance and accelerating the natural aging strengthening rate of the material.

[0046] The inventors discovered that adding sufficient Zr to the barrier layer can promote the formation of a layered Zr-containing second phase in the rolling direction during hot rolling, helping to inhibit vertical grain growth during recrystallization and promoting the formation of a fibrous structure. Compared to an equiaxed grain structure, a fibrous grain structure is more effective in preventing the vertical diffusion of Mg, thus preventing Mg from diffusing to the surface and causing brazing problems.

[0047] By designing the barrier layer elements, the average grain size of the barrier layer can be made 45-100 μm, and the grain aspect ratio can be ≥7.5 (prerequisite being that the barrier layer is added with the Zr element).

[0048] Preferably, the ratio of the thickness of the rapid aging aluminum alloy core material to the total thickness of the barrier layer is 7:3 to 8:2, for example, it can be 7:3, 7:2.5, 7:2, 7:1.8, 8:3, 8:2.5, 8:2.2 or 8:2, but is not limited to the listed values. Other values ​​not listed within this range are also applicable.

[0049] Preferably, the thickness ratio of the first barrier layer to the second barrier layer is 1:1 to 1:3, for example, it can be 1:1, 1:1.2, 1:1.3, 1:1.5, 1:1.8, 1:1.9, 1:2.0, 1:2.2, 1:2.3, 1:2.5, 1:2.8, 1:2.9 or 1:3, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0050] In a third aspect, the present invention provides a method for preparing the high-strength aluminum alloy composite plate material according to the second aspect, the preparation method comprising:

[0051] (1) The raw materials of the core material layer and the barrier layer are separately prepared according to the composition and weight percentage.

[0052] (2) The material obtained in step (1) is melted and cast to obtain a core layer aluminum ingot and a barrier layer aluminum ingot.

[0053] (3) homogenizing the core layer aluminum ingot obtained in step (2).

[0054] (4) The barrier layer and the core material layer are stacked according to a specific composite ratio, and hot-rolled composite materials are obtained after preheating.

[0055] (5) Cold rolling the hot-rolled composite material in step (4) to a target thickness to obtain a cold-rolled composite material.

[0056] (6) Annealing the cold-rolled composite material in step (5) to obtain a high-strength aluminum alloy composite plate.

[0057] The inventors found that by regulating a reasonable soaking process, a large amount of dispersed phase will be produced after soaking, and by regulating a reasonable hot rolling process, P texture will be formed in the annealing stage, which helps to increase the yield strength of the material.

[0058] Preferably, the heat treatment of the core layer aluminum ingot in step (3) includes: heating to 450-500°C at a heating rate of 100-300°C / h, keeping warm for 3-6 hours, then heating to 540-590°C at a heating rate of 60-150°C / h, keeping warm for 4-9 hours, and then cooling to room temperature.

[0059] After homogenization, the aluminum ingot is placed in the air to cool to room temperature. The purpose of homogenization is mainly to remove residual stress, eliminate dendritic segregation, fully dissolve the low-melting-point eutectic phase back into the matrix, and produce AlMnSi or AlCuMg dispersed phases. In addition, homogenization helps promote the transformation of AlMnFeCu phase into AlMnFeSiCu phase and α-Al. For core material ingots, if the first stage homogenization temperature is too low or the time is too short, it will make it difficult for the low-melting-point eutectic phase in the material to dissolve back into the matrix, resulting in overburning in the second stage of homogenization. If the first stage homogenization temperature is too high, it will also cause overburning. When the second stage homogenization temperature is low, not only will the amount of dispersed phase precipitation be severely reduced, but it will also lead to insufficient transformation of AlMnFeCu compounds; if the second stage homogenization temperature is too high, overburning will occur.

[0060] Specifically, the heating rate of the first stage is 100-300°C / h, for example, it can be 100°C / h, 123°C / h, 145°C / h, 167°C / h, 189°C / h, 212°C / h, 234°C / h, 256°C / h, 278°C / h or 300°C / h, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable. The insulation temperature of the first stage is 450-500°C, for example, it can be 450°C, 456°C, 462°C, 467°C, 473°C, 478°C, 484°C, 489°C, 495°C or 500°C, but is not limited to the listed values, and other values ​​not listed in this range are also applicable. The insulation time is 3-6h, for example, it can be 3h, 3.4h, 3.7h, 4h, 4.4h, 4.7h, 5h, 5.4h, 5.7h or 6h, but is not limited to the listed values, and other values ​​not listed in this range are also applicable. The heating rate of the second stage is 60-150°C / h, for example, it can be 60°C / h, 70°C / h, 80°C / h, 90°C / h, 100°C / h, 110°C / h, 120°C / h, 130°C / h, 140°C / h or 150°C / h, but is not limited to the listed values. Other values ​​not listed in this range are also applicable. The holding temperature of the second stage is 540-590°C, for example, it can be 540°C, 546°C, 55 2℃, 557℃, 563℃, 568℃, 574℃, 579℃, 585℃ or 590℃, etc., but not limited to the listed values, and other values ​​not listed in the range are also applicable. The insulation time is 4 to 9h, for example, it can be 4h, 4.6h, 5.2h, 5.7h, 6.3h, 6.8h, 7.4h, 7.9h, 8.5h or 9h, etc., but not limited to the listed values, and other values ​​not listed in the range are also applicable.

[0061] Preferably, the preheating temperature of the hot-rolled composite in step (4) is 450-500°C, for example, it can be 450°C, 456°C, 462°C, 467°C, 473°C, 478°C, 484°C, 489°C, 495°C or 500°C, but is not limited to the listed values. Other values ​​not listed within this range are also applicable. The preheating time is 2-3h, for example, it can be 2h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but is not limited to the listed values. Other values ​​not listed within this range are also applicable.

[0062] If the hot rolling temperature is too low, poor bonding and rolling cracking problems will occur. If the hot rolling temperature is too high, too much Mg element will diffuse to the surface of the core material, making it difficult to composite.

[0063] Preferably, the annealing temperature in step (6) is 350-400°C, for example, it can be 350°C, 356°C, 362°C, 367°C, 373°C, 378°C, 384°C, 389°C, 395°C or 400°C, but is not limited to the listed values. Other values ​​not listed within this range are also applicable. The annealing time is 1-3h, for example, it can be 1h, 1.3h, 1.5h, 1.7h, 1.9h, 2.2h, 2.4h, 2.6h, 2.8h or 3h, but is not limited to the listed values. Other values ​​not listed within this range are also applicable.

[0064] In a fourth aspect, the present invention provides a brazing method for the high-strength aluminum alloy composite plate material according to the second aspect, the brazing method comprising: brazing and aging the high-strength aluminum alloy composite plate material.

[0065] Preferably, the brazing temperature is 600-605°C, for example, it can be 600°C, 600.5°C, 601°C, 601.5°C, 602°C, 602.5°C, 603°C, 603.5°C, 604°C, 604.5°C or 605°C, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0066] Preferably, the brazing time is 3 to 15 minutes, for example, 3 minutes, 5 minutes, 6 minutes, 7 minutes, 9 minutes, 10 minutes, 11 minutes, 13 minutes, 14 minutes or 15 minutes, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0067] Preferably, the aging treatment includes: cooling to 150-250°C at a cooling rate of 15-40°C / min after brazing, and then cooling to room temperature at a cooling rate of 50-100°C / min, and then placing the material at room temperature for 1-2 weeks for natural aging treatment. Specifically, the cooling rate in the first stage is 15-40°C / min, for example, it can be 15°C / min, 18°C / min, 21°C / min, 24°C / min, 27°C / min, 29°C / min, 32°C / min, 35°C / min, 38°C / min or 40°C / min, but is not limited to the listed values, and other values ​​not listed in this range are also applicable. The temperature of the first stage is 150-250°C, for example, 150°C, 162°C, 173°C, 184°C, 195°C, 206°C, 217°C, 228°C, 239°C, or 250°C, but is not limited to the values ​​listed above. Other values ​​not listed within this range are also applicable. The cooling rate of the second stage is 50-100°C / min, for example, 50°C / min, 56°C / min, 62°C / min, 67°C / min, 73°C / min, 78°C / min, 84°C / min, 89°C / min, 95°C / min, or 100°C / min, but is not limited to the values ​​listed above. Other values ​​not listed within this range are also applicable. The placement time is 1-2 weeks, for example, 7 days, 8 days, 9 days, 10 days, 11 days, 12 days, 13 days, or 14 days.

[0068] Compared with the prior art, the present invention has at least the following beneficial effects:

[0069] (1) After brazing and natural aging for two weeks, the high-strength aluminum alloy composite plate provided by the present invention has a yield strength of ≥110 MPa, a tensile strength of ≥200 MPa, and an elongation of 16%.

[0070] (2) The high-strength aluminum alloy composite plate provided by the present invention has good fatigue performance, and its fatigue strength after brazing and natural aging is ≥115MPa.

[0071] (3) After brazing and natural aging, the strengthening phases in the core layer of the high-strength aluminum alloy composite plate provided by the present invention are divided into two categories: one is the dispersed phase, which is mainly composed of AlMnSi series dispersed phases and AlCuMg series dispersed phases; the other is the precipitation phase, which is mainly composed of Q' phase and β" phase. These two types of strengthening phases play the role of dispersion strengthening and precipitation strengthening, respectively.

[0072] (4) The components of the high-strength aluminum alloy composite plate provided by the present invention all contain common elements in aluminum alloys, so different types of aluminum alloy scraps can be added, and the scrap addition ratio is not less than 50%, which better meets the requirements of low-carbon production. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 The distribution diagram of the micron-sized phase after brazing of the high-strength aluminum alloy composite plate provided for Application Example 1.

[0074] Figure 2 The distribution diagram of the nano-sized phase after brazing of the high-strength aluminum alloy composite plate provided in Application Example 1. DETAILED DESCRIPTION

[0075] For the convenience of understanding the present invention, the present invention is given below with examples. It should be understood by those skilled in the art that the examples are only for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0076] Terms and Definitions

[0077] The term "aspect ratio" is also called the length-to-width ratio. For grain testing, the aspect ratio is the ratio of the longest diameter passing through the interior of the particle to the longest diameter perpendicular to it. This parameter is often used to describe grain morphology.

[0078] Test Method

[0079] 1. Element Content Evaluation: 40mm x 40mm x 10mm aluminum alloy block samples were cut from the cast barrier layer aluminum ingot and the core material aluminum ingot using a saw. The surfaces were polished with 80-grit and 240-grit sandpaper, respectively. The sample surfaces were then cleaned with alcohol to prepare the barrier layer and core material element content test samples. The samples were then tested using a SPECTROM10 direct-reading spectrometer produced by SPECTRO Germany at three locations. The final element content result was the average of the three values.

[0080] 2. Grain Size, Texture, and Microstructure Evaluation: The rapidly aged aluminum alloy core material and high-strength aluminum alloy composite plate were cut into 20 mm x 10 mm samples. The samples were then mounted with the longitudinal cross-section as the observation surface. The samples were then ground, polished, and vibratory polished to produce metallographic specimens with a core layer and a barrier layer. EBSD analysis was then performed using a Zeiss Sigma300 field emission electron microscope equipped with an EBSD probe. After the analysis, data was processed using AztecCrystal software, which uses its built-in data processing system to obtain data such as average grain size, grain aspect ratio, and texture fraction.

[0081] 3. Evaluation of the eutectic phase and the dispersed phase: The rapid-aging aluminum alloy core material and the high-strength aluminum alloy composite plate were cut into 20 mm × 10 mm samples. The longitudinal cross-section of the sample was used as the observation surface during mounting. The samples were then ground and polished in sequence to produce metallographic specimens having a core layer and a barrier layer. A Sigma300 field emission electron microscope produced by Zeiss, Germany, was used to observe the distribution of the eutectic phase at a magnification of 500-1000, and the composition of the eutectic phase was determined in combination with EDS. The distribution of the dispersed phase was observed at a magnification of 5000-10000, and the composition of the dispersed phase was determined in combination with EDS.

[0082] 4. Evaluation of precipitated phases: After the rapid aging aluminum alloy core material and the high-strength aluminum alloy composite plate were cut into 15 mm × 15 mm sizes, they were polished and thinned using 400 mesh, 800 mesh, 1200 mesh, and 2400 mesh sandpaper, respectively, and the final sample thickness was 70 to 100 nm; the sample was then punched into a projection sample with a diameter of 3 mm using a wafer punch; the transmission sample was then electrolytically double-sprayed in a solution of 30 vol% nitric acid + 70 vol% methanol to complete the preparation of the transmission sample; a TECNAI transmission electron microscope produced by FEI, USA, was used at a voltage of 200 kV and a magnification of 2500 to 20,000 to observe the type and distribution of the magnesium-silicon precipitated phase; at the same time, EDS was used to test the composition of the precipitated phase.

[0083] 5. Tensile Properties Testing: Mechanical properties of the prepared rapidly aged aluminum alloy core material, high-strength aluminum alloy composite sheet, and high-strength aluminum alloy composite sheet after brazing and aging were tested using the methods outlined in GB / T228.1-2010, "Tensile Testing of Metallic Materials - Part 1: Room Temperature Test Methods." A ZWICK universal testing machine was used. The tested parameters included yield strength, tensile strength, and elongation at room and elevated temperatures. These are referred to as plastic extension strength (Rp0.2), tensile strength (Rm), and elongation after fracture (A50) in the test method, respectively. In the industry, these are commonly referred to as yield strength, tensile strength, and elongation, respectively.

[0084] 6. Evaluation of fatigue performance: The fatigue performance of high-strength aluminum alloy composite plates is tested using the method disclosed in GB / T3075-2021 "Axial force control method for fatigue testing of metal materials", and the test indicator is fatigue strength.

[0085] Core layer

[0086] Core material layer X1: includes the following alloy components in percentage by mass: Si: 0.5%, Mn: 1.0%, Mg: 1.2%, Cu: 1.2%, Fe: 0.8%; Zr: 0.01%, wherein Mg / Si is 2.4.

[0087] Core material layer X2: includes the following alloy components in percentage by mass: Si: 0.8%, Mn: 2.0%, Mg: 0.56%, Cu: 2.4%, Fe: 0.20%; Zr: 0.2%, wherein Mg / Si is 0.7.

[0088] Core material layer X3: includes the following alloy components in percentage by mass: Si: 0.6%, Mn: 0.70%, Mg: 0.40%, Cu: 1.40%, Fe: 1.10%; Zr: 0.01%, wherein Mg / Si is 0.67.

[0089] Core material layer X4: includes the following alloy components in percentage by mass: Si: 0.85%, Mn: 2.00%, Mg: 0.56%, Cu: 2.40%, Fe: 0.20%; Zr: 0.20%, wherein Mg / Si is 0.66.

[0090] Core material layer X5: includes the following alloy components in percentage by mass: Si: 0.4%, Mn: 1.0%, Mg: 1.20%, Cu: 1.20%, Fe: 0.80%; Zr: 0.10%, wherein Mg / Si is 3.0.

[0091] Core material layer X6: includes the following alloy components by mass percentage: Si: 0.50%, Mn: 1.00%, Mg: 0.60%, Cu: 1.20%, Fe: 0.80%; Mg / Si is 1.2.

[0092] Core material layer X7: includes the following alloy components in percentage by mass: Si: 0.3%, Mn: 0.6%, Mg: 1.5%, Cu: 1.6%, Fe: 1.7%; Zr: 0.01%, wherein Mg / Si is 5.00.

[0093] Core material layer XD1: includes the following alloy components by mass percentage: Si: 0.2%, Mn: 1.00%, Mg: 0.60%, Cu: 1.20%, Fe: 0.80%; wherein Mg / Si is 3.00.

[0094] The core material layer XD2 includes the following alloy components by mass percentage: Si: 0.50%, Mn: 0.30%, Mg: 0.60%, Cu: 1.20%, Fe: 0.80%; wherein the Mg / Si ratio is 1.2.

[0095] Core material layer XD3: includes the following alloy components in percentage by mass: Si: 0.50%, Mn: 1.00%, Mg: 0.30%, Cu: 1.20%, Fe: 0.80%; wherein Mg / Si is 0.60.

[0096] Core material layer XD4: includes the following alloy components by mass percentage: Si: 0.50%, Mn: 1.00%, Mg: 0.60%, Cu: 0.60%, Fe: 0.80%; wherein Mg / Si is 1.2.

[0097] barrier layer

[0098] Barrier layer Z1: comprises the following alloy components in percentage by mass: Zr: 1.0%, Ti: 0.05%, Cu: 1%.

[0099] Barrier layer Z2: includes the following alloy components in terms of mass percentage: Cu: 1.5%.

[0100] Barrier layer Z3: comprises the following alloy components in percentage by mass: Zr: 0.1%, Ti: 0.1%, Cu: 1%.

[0101] Example 1

[0102] This embodiment provides a high-strength aluminum alloy composite plate F1, which includes a core material layer and a barrier layer arranged on the surface of the core material layer. The barrier layer includes a first barrier layer and a second barrier layer arranged on the surfaces of both sides of the core material layer. The core material layer is made of core material layer X1, and the first barrier layer and the second barrier layer are both made of barrier layer Z1. The total thickness ratio of the core material layer to the barrier layer is 7.5:2.5, and the thickness ratio of the first barrier layer to the second barrier layer is 1:1.5.

[0103] The core material layer is a rapid aging aluminum alloy core material. AlMnSi dispersed phases are detected in the rapid aging aluminum alloy core material, including: AlMnSiFeCu dispersed phase, AlMnSi dispersed phase, and AlCuMg dispersed phase, including: AlCuMg dispersed phase, AlCuMgZr dispersed phase. The total number density of these dispersed phases is ≥8.5×10 5 Pieces / mm 2 The number density of AlCuMgZr dispersed phase is 9.3×10 4 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 15.5%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 23.5 μm. The average grain size of the barrier layer is 63.7 μm, and the grain aspect ratio is 12.3.

[0104] This embodiment also provides a method for preparing the high-strength aluminum alloy composite plate, which comprises:

[0105] (1) preparing the raw materials of the core material layer and the barrier layer according to the composition and weight percentage;

[0106] (2) smelting the material obtained in step (1), refining, removing impurities, and degassing the smelting process, and then casting it into aluminum ingots, and cutting the ingots, trimming the ingots, and milling the ingots to remove the parts with uneven composition, thereby obtaining core layer aluminum ingots and barrier layer aluminum ingots;

[0107] (3) homogenizing the core layer aluminum ingot and the barrier layer aluminum ingot obtained in step (2);

[0108] The homogenization treatment of the core layer aluminum ingot includes: heating to 490°C at a heating rate of 250°C / h, keeping warm for 5 hours, then heating to 570°C at a heating rate of 100°C / h, keeping warm for 6 hours, and then cooling to room temperature.

[0109] The barrier layer aluminum ingot does not need to be homogenized.

[0110] (4) laminating the barrier layer and the core material layer according to the composite ratio of the first barrier layer, the core material layer, and the barrier layer, and then preheating at 480° C. for 2.5 h and then hot rolling to obtain a hot-rolled composite material;

[0111] (5) cold rolling the hot-rolled composite material of step (4) to a target thickness to obtain a cold-rolled composite material;

[0112] (6) Annealing the cold-rolled composite material in step (5) at 380° C. for 2 h to obtain a high-strength aluminum alloy composite plate.

[0113] Example 2

[0114] This embodiment provides a high-strength aluminum alloy composite plate F2, which includes a core material layer and a barrier layer arranged on the surface of the core material layer, wherein the barrier layer includes a first barrier layer and a second barrier layer arranged on the two side surfaces of the core material layer, wherein the material of the core material layer is the core material layer X2, the material of the first barrier layer and the second barrier layer are both the barrier layer Z2, the total thickness ratio of the core material layer to the barrier layer is 7:3, and the thickness ratio of the first barrier layer to the second barrier layer is 1:1.

[0115] The core material layer is a rapid aging aluminum alloy core material. AlMnSi dispersed phases are detected in the rapid aging aluminum alloy core material, including: AlMnSiFeCu dispersed phase, AlMnSi dispersed phase, and AlCuMg dispersed phase, including: AlCuMg dispersed phase, AlCuMgZr dispersed phase. The total number density of these dispersed phases is ≥11.1×10 5 Pieces / mm 2The number density of AlCuMgZr dispersed phase is 8.2×10 4 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 18.2%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 24.4 μm. The average grain size of the barrier layer is 120.3 μm, with a grain aspect ratio of 4.5.

[0116] This embodiment also provides a method for preparing the high-strength aluminum alloy composite plate, which comprises:

[0117] (1) preparing the raw materials of the core material layer and the barrier layer according to the composition and weight percentage;

[0118] (2) smelting the material obtained in step (1), refining, removing impurities, and degassing the smelting process, and then casting it into aluminum ingots, and cutting the ingots, trimming the ingots, and milling the ingots to remove the parts with uneven composition, thereby obtaining core layer aluminum ingots and barrier layer aluminum ingots;

[0119] (3) homogenizing the core layer aluminum ingot and the barrier layer aluminum ingot obtained in step (2);

[0120] The homogenization treatment of the core layer aluminum ingot includes: heating to 500°C at a heating rate of 100°C / h, keeping warm for 3 hours, then heating to 540°C at a heating rate of 60°C / h, keeping warm for 9 hours, and then cooling to room temperature.

[0121] The barrier layer aluminum ingot does not need to be homogenized.

[0122] (4) laminating the barrier layer and the core material layer according to the composite ratio of the first barrier layer, the core material layer, and the barrier layer, and then preheating at 450° C. for 3 h and then hot rolling the composite material to obtain a hot-rolled composite material;

[0123] (5) cold rolling the hot-rolled composite material of step (4) to a target thickness to obtain a cold-rolled composite material;

[0124] (6) Annealing the cold-rolled composite material in step (5) at 350° C. for 3 h to obtain a high-strength aluminum alloy composite plate.

[0125] Example 3

[0126] This embodiment provides a high-strength aluminum alloy composite plate F3, which includes a core material layer and a barrier layer arranged on the surface of the core material layer, wherein the barrier layer includes a first barrier layer and a second barrier layer arranged on the two side surfaces of the core material layer, wherein the material of the core material layer is the core material layer X3, the material of the first barrier layer and the second barrier layer are both the barrier layer Z3, the total thickness ratio of the core material layer to the barrier layer is 8:2, and the thickness ratio of the first barrier layer to the second barrier layer is 1:3.

[0127] The core material layer is a rapid aging aluminum alloy core material. AlMnSi dispersed phases are detected in the rapid aging aluminum alloy core material, including: AlMnSiFeCu dispersed phase, AlMnSi dispersed phase, and AlCuMg dispersed phase, including: AlCuMg dispersed phase, AlCuMgZr dispersed phase. The total number density of these dispersed phases is ≥5.5×10 5 Pieces / mm 2 The number density of AlCuMgZr dispersed phase is 4.2×10 4 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 11.9%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 26.3 μm. The average grain size of the barrier layer is 91.3 μm, and the grain aspect ratio is 10.6.

[0128] This embodiment also provides a method for preparing the high-strength aluminum alloy composite plate, which comprises:

[0129] (1) preparing the raw materials of the core material layer and the barrier layer according to the composition and weight percentage;

[0130] (2) smelting the material obtained in step (1), refining, removing impurities, and degassing the smelting process, and then casting it into aluminum ingots, and cutting the ingots, trimming the ingots, and milling the ingots to remove the parts with uneven composition, thereby obtaining core layer aluminum ingots and barrier layer aluminum ingots;

[0131] (3) homogenizing the core layer aluminum ingot and the barrier layer aluminum ingot obtained in step (2);

[0132] The homogenization treatment of the core layer aluminum ingot includes: heating to 480°C at a heating rate of 300°C / h, keeping warm for 6 hours, then heating to 590°C at a heating rate of 150°C / h, keeping warm for 4 hours, and then cooling to room temperature.

[0133] The barrier layer aluminum ingot does not need to be homogenized.

[0134] (4) laminating the barrier layer and the core material layer according to the composite ratio of the first barrier layer, the core material layer, and the barrier layer, and then preheating at 500° C. for 2 h and hot rolling to obtain a hot-rolled composite material;

[0135] (5) cold rolling the hot-rolled composite material of step (4) to a target thickness to obtain a cold-rolled composite material;

[0136] (6) Annealing the cold-rolled composite material in step (5) at 400° C. for 1 h to obtain a high-strength aluminum alloy composite plate.

[0137] Example 4

[0138] This embodiment provides a high-strength aluminum alloy composite plate F4. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate F4 and the embodiment 1 is that the material of the core layer is the core layer X4. The rest is the same as the embodiment 2 and will not be repeated here.

[0139] The core layer of the high-strength aluminum alloy composite plate obtained in this embodiment is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases and AlMnSi dispersed phases, as well as AlCuMg dispersed phases, including AlCuMg dispersed phases and AlCuMgZr dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 11.3×10 5 Pieces / mm 2 The number density of AlCuMgZr dispersed phase is 7.5×10 4 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 16.5%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 22.9 μm. The average grain size of the barrier layer is 126.9 μm, with a grain aspect ratio of 4.1.

[0140] Example 5

[0141] This embodiment provides a high-strength aluminum alloy composite plate F5. The difference between the raw materials and preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the material of the core layer is core layer X5. The rest is the same as Example 1 and will not be repeated here.

[0142] The core layer of the high-strength aluminum alloy composite plate obtained in this embodiment is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases and AlMnSi dispersed phases, as well as AlCuMg dispersed phases, including AlCuMg dispersed phases and AlCuMgZr dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 7.2×10 5 Pieces / mm 2 The number density of AlCuMgZr dispersed phase is 9.4×10 4 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 15.3%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 28.5 μm. The average grain size of the barrier layer is 60.5 μm, and the grain aspect ratio is 11.7.

[0143] Example 6

[0144] This embodiment provides a high-strength aluminum alloy composite plate F6. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate F6 and the embodiment 1 is that the material of the core layer is the core layer X6. The rest is the same as the embodiment 1 and will not be repeated here.

[0145] The core layer of the high-strength aluminum alloy composite plate obtained in this embodiment is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases, AlMnSi dispersed phases, and AlCuMg dispersed phases, including AlCuMg dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 7.2×10 5 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 8.8%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 23.1 μm. The average grain size of the barrier layer is 65.3 μm, with a grain aspect ratio of 12.3.

[0146] Example 7

[0147] This embodiment provides a high-strength aluminum alloy composite plate F7, which includes a core material layer and a barrier layer arranged on the surface of the core material layer, wherein the barrier layer includes a first barrier layer and a second barrier layer arranged on the two side surfaces of the core material layer, wherein the material of the core material layer is the core material layer X7, the material of the first barrier layer and the second barrier layer are both the barrier layer Z1, the total thickness ratio of the core material layer to the barrier layer is 7.5:2.5, and the thickness ratio of the first barrier layer to the second barrier layer is 1:1.5.

[0148] The core material layer is a rapid aging aluminum alloy core material. AlMnSi dispersed phases are detected in the rapid aging aluminum alloy core material, including: AlMnSiFeCu dispersed phase, AlMnSi dispersed phase, and AlCuMg dispersed phase, including: AlCuMg dispersed phase, AlCuMgZr dispersed phase. The total number density of these dispersed phases is ≥5.5×10 5 Pieces / mm 2 The number density of AlCuMgZr dispersed phase is 4.5×10 4 Pieces / mm 2 The rapid-aging aluminum alloy core material has a P texture ratio of 11.3%. The rapid-aging aluminum alloy core material does not contain coarse compounds. The coarse compounds include AlMnFeSiCu compounds with a long diameter greater than 30 μm and / or AlMnFeCu compounds with a long diameter greater than 30 μm. The maximum long diameter of the compounds in the rapid-aging aluminum alloy core material is 29.2 μm. The average grain size of the barrier layer is 60.7 μm, and the grain aspect ratio is 12.1.

[0149] This embodiment also provides a method for preparing the high-strength aluminum alloy composite plate, which comprises:

[0150] (1) preparing the raw materials of the core material layer and the barrier layer according to the composition and weight percentage;

[0151] (2) smelting the material obtained in step (1), refining, removing impurities, and degassing the smelting process, and then casting it into aluminum ingots, and cutting the ingots, trimming the ingots, and milling the ingots to remove the parts with uneven composition, thereby obtaining core layer aluminum ingots and barrier layer aluminum ingots;

[0152] (3) homogenizing the core layer aluminum ingot and the barrier layer aluminum ingot obtained in step (2);

[0153] The homogenization treatment of the core layer aluminum ingot includes: heating to 450°C at a heating rate of 200°C / h, keeping warm for 4 hours, then heating to 580°C at a heating rate of 80°C / h, keeping warm for 5 hours, and then cooling to room temperature.

[0154] The barrier layer aluminum ingot does not need to be homogenized.

[0155] (4) laminating the barrier layer and the core material layer according to the composite ratio of the first barrier layer, the core material layer, and the barrier layer, and then preheating at 460° C. for 2.5 h and then hot rolling to obtain a hot-rolled composite material;

[0156] (5) cold rolling the hot-rolled composite material of step (4) to a target thickness to obtain a cold-rolled composite material;

[0157] (6) Annealing the cold-rolled composite material in step (5) at 380° C. for 2 h to obtain a high-strength aluminum alloy composite plate.

[0158] Comparative Example 1

[0159] This comparative example provides a high-strength aluminum alloy composite plate DF1. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the material of the core layer is the core layer DX1. The rest is the same as Example 6 and will not be repeated here.

[0160] The core layer of the high-strength aluminum alloy composite plate obtained in this comparative example is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases, AlMnSi dispersed phases, and AlCuMg dispersed phases, including AlCuMg dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 2.3×10 5 Pieces / mm 2 , and the P texture accounts for 6.9% in the rapid aging aluminum alloy core material; the maximum major axis size of the compound in the rapid aging aluminum alloy core material is 45.9 μm; the average grain size of the barrier layer is 59.4 μm, and the grain aspect ratio is 11.1.

[0161] Comparative Example 2

[0162] This comparative example provides a high-strength aluminum alloy composite plate DF2. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the material of the core layer is the core layer DX2. The rest is the same as Example 6 and will not be repeated here.

[0163] The core material layer of the high-strength aluminum alloy composite plate obtained in this comparative example is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases, AlMnSi dispersed phases, and AlCuMg dispersed phases, including AlCuMg dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 2.2×10 5 Pieces / mm 2, and the P texture accounts for 6.1% in the rapid aging aluminum alloy core material; the maximum major axis size of the compound in the rapid aging aluminum alloy core material is 20.5 μm; the average grain size of the barrier layer is 68.1 μm, and the grain aspect ratio is 12.5.

[0164] Comparative Example 3

[0165] This comparative example provides a high-strength aluminum alloy composite plate DF3. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the material of the core layer is the core layer DX3, and the rest is the same as Example 6, which will not be repeated here.

[0166] The core layer of the high-strength aluminum alloy composite plate obtained in this comparative example is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases, AlMnSi dispersed phases, and AlCuMg dispersed phases, including AlCuMg dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 6.3×10 5 Pieces / mm 2 , and the P texture accounts for 6.5% in the rapid aging aluminum alloy core material; the maximum major axis size of the compound in the rapid aging aluminum alloy core material is 24.5 μm; the average grain size of the barrier layer is 66.4 μm, and the grain aspect ratio is 12.9.

[0167] Comparative Example 4

[0168] This comparative example provides a high-strength aluminum alloy composite plate DF4. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the material of the core layer is the core layer DX4. The rest is the same as Example 6 and will not be repeated here.

[0169] The core layer of the high-strength aluminum alloy composite plate obtained in this comparative example is a rapid aging aluminum alloy core material. AlMnSi dispersed phases, including AlMnSiFeCu dispersed phases, AlMnSi dispersed phases, and AlCuMg dispersed phases, including AlCuMg dispersed phases, were detected in the rapid aging aluminum alloy core material. The total number density of the dispersed phases was 6.7×10 5 Pieces / mm 2 , and the P texture accounts for 7.2% in the rapid aging aluminum alloy core material; the maximum major axis size of the compound in the rapid aging aluminum alloy core material is 31.5 μm; the average grain size of the barrier layer is 57.6 μm, and the grain aspect ratio is 11.6.

[0170] Comparative Example 5

[0171] This comparative example provides a high-strength aluminum alloy composite plate DF5. The difference between the raw materials and preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the homogenization treatment of the core material layer aluminum ingot in step (3) includes: first heating to 550°C at a heating rate of 250°C / h and keeping warm for 5h. The rest is the same as Example 1 and will not be repeated here.

[0172] Comparative Example 6

[0173] This comparative example provides a high-strength aluminum alloy composite plate DF6. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate and Example 1 is that the homogenization treatment of the core material layer aluminum ingot in step (3) includes: first heating to 400°C at a heating rate of 250°C / h and keeping warm for 5h. The rest is the same as Example 1 and will not be repeated here.

[0174] The materials in Comparative Examples 5 to 6 were scrapped due to overburning. Specifically, the low temperature in the first section would cause the low-melting-point eutectic phase to melt back slowly, resulting in overburning during the second heating process; if the temperature in the first section was too high, it would directly overburn.

[0175] Comparative Example 7

[0176] This comparative example provides a high-strength aluminum alloy composite plate DF7. The difference between the raw materials and the preparation process of the high-strength aluminum alloy composite plate DF7 and Example 1 is that: in step (4), hot rolling and compounding are carried out after preheating at 400°C for 2.5 hours. The rest is the same as Example 1 and will not be repeated here.

[0177] In this comparative example, due to the low preheating temperature, the barrier layer and the core material layer had poor adhesion during hot rolling and lamination, resulting in peeling and the material was scrapped.

[0178] Comparative Example 8

[0179] This comparative example provides a high-strength aluminum alloy composite plate DF8. The difference between the raw materials and preparation process of the high-strength aluminum alloy composite plate DF8 and those in Example 1 is that in step (4), hot rolling and compounding are performed after preheating at 520°C for 2.5 hours. The rest is the same as in Example 1 and will not be repeated here.

[0180] Since the preheating temperature of the high-strength aluminum alloy composite plate obtained in this comparative example is too high, the Mg element diffuses to the surface of the core material layer, making it difficult to successfully hot-roll composite, and no hot-rolled composite material can be obtained.

[0181] The mechanical properties of the high-strength aluminum alloy composite plates obtained in the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0182] Table 1

[0183] Yield strength Rp0.2 (MPa) Tensile strength Rm (MPa) Elongation A50 (%) Example 1 72.9 178.3 21.8 Example 2 86.7 200.6 17.9 Example 3 63.0 172.5 24.1 Example 4 82.5 193.7 18.9 Example 5 70.8 175.6 17.5 Example 6 63.4 170.9 21.8 Example 7 68.7 173.1 19.5 Comparative Example 1 57.7 165.9 15.4 Comparative Example 2 60.1 155.1 22.1 Comparative Example 3 54.1 158.9 20.6 Comparative Example 4 60.2 154.4 17.1

[0184] Application Example 1

[0185] This application example provides a brazing method for a high-strength aluminum alloy composite plate. The brazing method comprises: brazing the high-strength aluminum alloy composite plate F1 described in Example 1 at a brazing temperature of 603°C for 10 minutes, and then performing an aging treatment; the aging treatment comprises: cooling to 200°C at a cooling rate of 30°C / min after brazing, and then cooling to room temperature at a cooling rate of 80°C / min, and then placing the material at room temperature for 2 weeks for natural aging treatment to obtain a high-strength aluminum alloy composite plate after brazing and natural aging treatment. The P texture proportion in the high-strength aluminum alloy composite plate after brazing and natural aging treatment is 15.1%.

[0186] The distribution diagrams of the micron-sized phase and the nano-sized phase of the high-strength aluminum alloy composite plate after brazing and natural aging treatment provided in this application example are as follows: Figures 1 and 2 shown.

[0187] Application Example 2

[0188] This application example provides a brazing method for a high-strength aluminum alloy composite plate, the brazing method comprising: brazing the high-strength aluminum alloy composite plate F2 described in Example 2 at a brazing temperature of 605°C for 3 minutes, and then performing an aging treatment; the aging treatment comprising: cooling to 150°C at a cooling rate of 15°C / min after brazing, and then cooling to room temperature at a cooling rate of 50°C / min, then placing the material at room temperature for 1 week and performing a natural aging treatment to obtain a high-strength aluminum alloy composite plate after brazing and natural aging treatment, wherein the P texture in the high-strength aluminum alloy composite plate after brazing and natural aging treatment accounts for 15.2%.

[0189] Application Example 3

[0190] This application example provides a brazing method for a high-strength aluminum alloy composite plate, the brazing method comprising: brazing the high-strength aluminum alloy composite plate F3 described in Example 3 at a brazing temperature of 600°C for 15 minutes, and then performing an aging treatment; the aging treatment comprising: cooling to 250°C at a cooling rate of 40°C / min after brazing, and then cooling to room temperature at a cooling rate of 100°C / min, and then placing the material at room temperature for 10 days for natural aging treatment to obtain a high-strength aluminum alloy composite plate after brazing and natural aging treatment, wherein the P texture in the high-strength aluminum alloy composite plate after brazing and natural aging treatment accounts for 10.2%.

[0191] Application Example 4

[0192] This application example provides a method for brazing a high-strength aluminum alloy composite sheet. This method differs from Application Example 2 only in that the high-strength aluminum alloy composite sheet F4 provided in Example 4 is used for brazing; otherwise, the method is the same as in Application Example 2. The brazed and naturally aged high-strength aluminum alloy composite sheet obtained in this application example has a P texture content of 12.2%.

[0193] Application Example 5

[0194] This application example provides a method for brazing a high-strength aluminum alloy composite sheet. This method differs from Application Example 1 only in that the high-strength aluminum alloy composite sheet F5 provided in Example 5 is used for brazing; otherwise, the method is the same as in Application Example 1. The brazed and naturally aged high-strength aluminum alloy composite sheet obtained in this application example has a P texture content of 14.8%.

[0195] Application Example 6

[0196] This application example provides a brazing method for a high-strength aluminum alloy composite sheet. This brazing method differs from Application Example 1 only in that the high-strength aluminum alloy composite sheet F6 provided in Example 6 is used for brazing; otherwise, the brazing method is identical to Application Example 1. The brazed and naturally aged high-strength aluminum alloy composite sheet obtained in this application example has a P texture content of 6.7%.

[0197] Application Example 7

[0198] This application example provides a brazing method for a high-strength aluminum alloy composite plate, the brazing method comprising: brazing the high-strength aluminum alloy composite plate F7 described in Example 7 at a brazing temperature of 602°C for 7 minutes, and then performing an aging treatment; the aging treatment comprising: cooling to 200°C at a cooling rate of 35°C / min after brazing, and then cooling to room temperature at a cooling rate of 70°C / min, and then placing the material at room temperature for 10 days for natural aging treatment to obtain a high-strength aluminum alloy composite plate after brazing and natural aging treatment, wherein the P texture in the high-strength aluminum alloy composite plate after brazing and natural aging treatment accounts for 10.9%.

[0199] Comparative Application Example 1

[0200] This comparative example provides a brazing method for a high-strength aluminum alloy composite sheet. This method differs from Example 6 only in that the brazing is performed using the high-strength aluminum alloy composite sheet DF1 provided in Comparative Example 1. All other aspects are the same as in Example 6. The brazing and naturally aged high-strength aluminum alloy composite sheet obtained in this example has a P texture content of 4.9%.

[0201] Application Comparative Example 2

[0202] This comparative example provides a brazing method for a high-strength aluminum alloy composite sheet. This brazing method differs from Example 6 only in that the high-strength aluminum alloy composite sheet DF2 provided in Comparative Example 2 is used for brazing; otherwise, all other aspects are the same as Example 6. The brazing and naturally aged high-strength aluminum alloy composite sheet obtained in this example has a P texture content of 4.1%.

[0203] Application Comparative Example 3

[0204] This comparative example provides a brazing method for a high-strength aluminum alloy composite sheet. This brazing method differs from Example 6 only in that the high-strength aluminum alloy composite sheet DF3 provided in Comparative Example 3 is used for brazing; otherwise, all other aspects are the same as in Example 6. The brazing and naturally aged high-strength aluminum alloy composite sheet obtained in this example has a P texture content of 4.6%.

[0205] Comparative Application Example 4

[0206] This comparative example provides a brazing method for a high-strength aluminum alloy composite sheet. This brazing method differs from Example 6 only in that the high-strength aluminum alloy composite sheet DF4 provided in Comparative Example 4 is used for brazing; otherwise, all other aspects are the same as in Example 6. The brazed and naturally aged high-strength aluminum alloy composite sheet obtained in this example has a P texture content of 5.4%.

[0207] The mechanical properties of the high-strength aluminum alloy composite plates obtained by brazing and naturally aging treatment in the corresponding example and application comparison example were tested, and the test results are shown in Table 2.

[0208] Table 2

[0209]

[0210] From Tables 1 and 2, we can see the following points:

[0211] (1) Comprehensive application examples 1 to 7 show that the high-strength aluminum alloy composite plate provided by the present invention has good fatigue performance. After brazing and natural aging, its fatigue strength is ≥115 MPa, the elongation is >16%, the tensile strength is above 200 MPa, and the yield strength Rp0.2 is above 110 MPa, with excellent performance.

[0212] (2) Influence of total dispersed phase number density

[0213] 2.1. Influence of Si element: By comparing Application Example 6 and Comparative Example 1, it can be seen that when the Si content is insufficient, the total number density of the dispersed phase in the core material will be insufficient, and the proportion of P texture in the core material layer will be low, resulting in a significant decrease in the tensile strength and yield strength of the high-strength aluminum alloy composite plate.

[0214] 2.2. Influence of Mn Element: By comparing Application Example 6 and Application Comparative Example 2, it can be seen that the insufficient Mn content in Application Comparative Example 2 leads to insufficient total number density of the dispersed phase in the core material and a low proportion of P texture, resulting in a significant decrease in the tensile strength and yield strength of the high-strength aluminum alloy composite plate.

[0215] 2.3. Influence of Mg element: By comparing Application Example 6 and Application Comparative Example 3, it can be seen that the insufficient Mg content in Application Comparative Example 3 leads to insufficient total number density of the dispersed phase in the core material and a low proportion of P texture, resulting in a significant decrease in the tensile strength and yield strength of the high-strength aluminum alloy composite plate.

[0216] 2.4. Effect of Cu Element: By comparing Application Example 6 and Comparative Example 4, it can be seen that the insufficient Cu content in Comparative Example 4 leads to insufficient total number density of the dispersed phase in the core material and a low proportion of P texture, resulting in a significant decrease in the tensile strength and yield strength of the high-strength aluminum alloy composite plate.

[0217] (3) Influence of AlCuMg dispersed phase

[0218] Influence of Mg / Si ratio: By comparing Application Example 2 and Application Example 4, it can be seen that the Mg / Si ratio in the high-strength aluminum alloy composite plate F4 is relatively low, and the proportion of AlCuMg dispersed phase is lower than that of the high-strength aluminum alloy composite plate F2. When the total dispersed phase density is equivalent, the proportion of P texture in the core layer of the high-strength aluminum alloy composite plate F4 is lower than that of the high-strength aluminum alloy composite plate F2. Finally, the proportion of P texture after brazing and aging treatment also decreases accordingly. Finally, the tensile strength and yield strength of the high-strength aluminum alloy composite plate in Application Example 4 after brazing are significantly lower than those in Application Example 2. This shows that the present invention preferably controls the Mg / Si ratio to be greater than 0.7, which can be more conducive to the formation of AlCuMg dispersed phases, especially AlCuMgZr dispersed phases, and can also increase the proportion of P texture after brazing, thereby ultimately improving the yield strength and tensile strength of the high-strength aluminum alloy composite plate after brazing and aging.

[0219] (4) Influence of AlCuMgZr dispersed phase

[0220] Effect of Zr element addition: By comparing Application Example 1 and Application Example 6, it can be seen that the core material layer of the high-strength aluminum alloy composite plate F6 does not contain Zr element, and the dispersed phase formed does not contain AlCuMgZr phase. Although the total number density of the dispersed phase in the core material is acceptable, the proportion of P texture formed after annealing treatment is significantly reduced compared with the high-strength aluminum alloy composite plate F1. Finally, the tensile strength and yield strength of the high-strength aluminum alloy composite plate after brazing and aging treatment are lower than those of Application Example 1, indicating that the AlCuMgZr phase formed by the Zr element in the core material layer can form more P texture after heat treatment, thereby ultimately improving the tensile strength and yield strength of the high-strength aluminum alloy composite plate.

[0221] (5) Influence of coarse compounds

[0222] 5.1 Effect of Si Content: Comparing Application Example 1 and Application Example 5, it can be seen that the core material layer of Application Example 5 contains insufficient silicon, resulting in insufficient conversion of Al6(FeMn) compounds. After annealing, the maximum major diameter of the coarse compounds in the core material layer is larger than that of Application Example 1, resulting in a decrease in the elongation of the high-strength aluminum alloy composite sheet. This indicates that the addition of an appropriate amount of Si content is beneficial for reducing the maximum major diameter of the coarse compounds in the core material layer and improving the elongation of the high-strength aluminum alloy composite sheet. Comparing Application Example 6 and Comparative Example 1, it can be seen that when the Si content is lower, the maximum major diameter of the coarse compounds in the core material layer is larger, resulting in a more serious decrease in the elongation of the high-strength aluminum alloy composite sheet.

[0223] 5.2. Effect of Cu Element: By comparing Application Example 6 and Comparative Example 4, it can be seen that the insufficient Cu content in Comparative Example 4 leads to an increase in the maximum major diameter of the coarse compounds in the core material, and ultimately the tensile strength and yield strength of the high-strength aluminum alloy composite plate after brazing and aging decrease.

[0224] The present invention uses the above-described embodiments to illustrate the detailed features of the present invention. However, the present invention is not limited to the above-described detailed features, which does not mean that the present invention must rely on the above-described detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for the selected technical features of the present invention, additions to auxiliary technical features, and selections of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A rapid aging aluminum alloy core material, characterized in that: The rapid aging aluminum alloy core material comprises the following alloy components in terms of mass percentage: Si: 0.3-0.8%, Mn: 0.6-2.0%, Mg: 0.4-1.5%, Cu: 1.2-2.4%, Fe≤1.7%; The total number density of AlMnSi series and AlCuMg series dispersed phases in the rapid aging aluminum alloy core material is ≥5.4×10 5 Pieces / mm 2 ; The P texture accounts for more than 10% in the rapid aging aluminum alloy core material.

2. The rapid aging aluminum alloy core material according to claim 1, characterized in that: The rapid aging aluminum alloy core material further comprises the following alloy components in terms of mass percentage: Zr: 0.01-0.2%; and the number density of the AlCuMgZr dispersed phase in the rapid aging aluminum alloy core material is ≥3×10 4 Pieces / mm 2 .

3. The rapid aging aluminum alloy core material according to claim 2, characterized in that: The ratio of the mass content of Mg to the mass content of Si in the rapid aging aluminum alloy core material is greater than 0.

7.

4. The rapid aging aluminum alloy core material according to any one of claims 1 to 3, characterized in that: The Fe content of the rapid aging aluminum alloy core material is 0.1-1.1%, preferably 0.5-1.1%; Preferably, in terms of mass percentage, the Si element in the rapid aging aluminum alloy core material is controlled to be 0.5-0.8%.

5. The rapid aging aluminum alloy core material according to any one of claims 1 to 4, characterized in that: The rapid aging aluminum alloy core material does not contain coarse compounds; the coarse compounds include AlMnFeSiCu compounds with a long diameter size greater than 30 μm, and / or AlMnFeCu compounds with a long diameter size greater than 30 μm.

6. The rapid aging aluminum alloy core material according to any one of claims 1 to 4, characterized in that: The rapid aging aluminum alloy core material also contains Ti element.

7. A high-strength aluminum alloy composite plate, characterized in that: The high-strength aluminum alloy composite plate comprises a core material layer and a barrier layer arranged on one side and / or both sides of the surface of the core material layer, wherein the core material layer is the rapid aging aluminum alloy core material according to any one of claims 1 to 6; Preferably, the barrier layer comprises a first barrier layer and a second barrier layer provided on both sides of the surface of the rapid aging aluminum alloy core material; Preferably, the barrier layer contains the following alloy components by weight percentage: Cu: 0.5-2.0%, Mg≤0.05%; Preferably, the barrier layer further contains Zr: 0.1-1wt% by weight; Preferably, the barrier layer further contains Ti: 0-0.1 wt % by weight.

8. A method for preparing the high-strength aluminum alloy composite plate according to claim 7, characterized in that: The preparation method comprises: (1) preparing the raw materials of the core material layer and the barrier layer according to the composition and weight percentage; (2) smelting and casting the material obtained in step (1) to obtain a core layer aluminum ingot and a barrier layer aluminum ingot; (3) homogenizing the core material layer aluminum ingot obtained in step (2); (4) laminating the barrier layer and the core material layer according to a specific composite ratio, and hot-rolling the composite material after preheating to obtain a hot-rolled composite material; (5) cold rolling the hot-rolled composite material of step (4) to a target thickness to obtain a cold-rolled composite material; (6) Annealing the cold-rolled composite material in step (5) to obtain a high-strength aluminum alloy composite plate.

9. The preparation method according to claim 8, characterized in that Step (3) of the soaking treatment of the core layer aluminum ingot comprises: heating the temperature to 450-500°C at a heating rate of 100-300°C / h, keeping the temperature for 3-6 hours, then heating the temperature to 540-590°C at a heating rate of 60-150°C / h, keeping the temperature for 4-9 hours, and then cooling to room temperature; Preferably, the preheating temperature of the hot rolling composite in step (4) is 450-500° C., and the preheating time is 2-3 hours; Preferably, the annealing temperature in step (6) is 350-400° C., and the annealing time is 1-3 hours.

10. A brazing method for the high-strength aluminum alloy composite plate according to claim 7, characterized in that: The brazing method comprises: brazing and aging the high-strength aluminum alloy composite plate.

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