Aluminum alloy composite material and preparation method thereof

Abstract

The invention discloses an aluminum alloy composite material and a preparation method thereof, and belongs to the field of aluminum alloy composite material preparation, the aluminum alloy composite material comprises a core material and a composite layer, the alloy of the core material comprises, by mass, 0.3-0.6% of Cu, 0.8-1.5% of Mn, 0.05-0.25% of Ti, Si and Fe not higher than 0.5%, the content of other single elements not higher than 0.05%, and the balance aluminum; the alloy of the composite layer comprises: 6.8 to 8.2% of Si, 0.8 to 1.2% of Zn, lt; 0.3% of Fe, lt; 0.15% of Cu, less than or equal to 0.05 wt% of other single elements, and the balance of aluminum; wherein the content of the element Zn in the composite layer is not lower than 0.7% after brazing diffusion volatilization; the longitudinal average grain size of the aluminum alloy composite material after brazing is not less than 400 microns; the aluminum alloy composite material prepared through the method is high in corrosion resistance, large in internal grain, good in weldability, uniform in brazing and long in service life.

Description

Technical Field

[0001] The invention belongs to the field of aluminum alloy material manufacturing, and specifically relates to an aluminum alloy composite material and a preparation method thereof. Background Art

[0002] The materials used in automotive heat exchangers need to have strong corrosion resistance requirements and need to adapt to harsh environments. Traditional automotive heat exchanger materials use ordinary composite plates, which have certain defects in brazing fluidity, corrosion resistance, and service life. Summary of the invention

[0003] In order to solve the above problems, the present invention provides an aluminum alloy composite material and a preparation method thereof. The specific technical scheme is as follows:

[0004] An aluminum alloy composite material, wherein the material of the aluminum alloy composite material is a multilayer composite material, the multilayer composite material comprises a core material and a composite layer, and the alloy of the core material comprises (mass fraction):

[0005] 0.3-0.6% Cu,

[0006] 0.8-1.5% Mn,

[0007] 0.05-0.25% Ti,

[0008] The mass ratio of Si to Fe is not higher than 0.5%,

[0009] The mass fraction of a single element is ≤0.05% and the mass fraction of other elements is ≤0.15%, the balance being aluminum;

[0010] The alloy of the composite layer comprises (mass fraction):

[0011] 6.8-8.2% Si,

[0012] 0.8-1.2% Zn,

[0013] <0.3% Fe,

[0014] <0.15% Cu,

[0015] Other elements with a single element content of ≤ 0.05%, the balance being aluminum; of which:

[0016] The content of Zn in the composite layer after diffusion and volatilization during brazing is not less than 0.7%;

[0017] The average grain size of the aluminum alloy composite material in the longitudinal direction after brazing is not less than 400 μm.

[0018] The preparation method of the above aluminum alloy composite material comprises the following specific steps:

[0019] Step 1: Take the traditional aluminum ingot and melt it to obtain the core material ingot, and then saw it into shape;

[0020] Step 2: Heat treat the finished product of step 1, and then mill the surface to obtain a preliminary aluminum product;

[0021] Step 3: Take the aluminum product in step 2 and add two layers of composite plates for compounding, hot rolling and cold rolling, and make a coil of specified specifications;

[0022] Step 4: annealing the coil in step 3;

[0023] Step 5: Stretch the coiled material in step 4, the deformation of the first stretching is controlled at 1.5-2.5%, then place it for the second stretching, the deformation of the second stretching is controlled at 2.5-3.5%, and the total stretching deformation is controlled at 4-5%.

[0024] Step 6: Anneal the coiled material in step 5 at a temperature of 150-200°C, and cut and shape the coiled material after cooling.

[0025] As a further improvement, it is characterized in that the thickness of the outer composite layer and the inner composite layer are 8% and 10% of the thickness of the multi-layer composite material respectively.

[0026] The present invention provides an aluminum alloy composite material and a preparation method thereof. The three-layer plate is composited, and then hot-rolled, cold-rolled, annealed, and then stretched to deform the grains in the longitudinal direction. The grains are then annealed to grow the grains deformed in the longitudinal direction. After brazing, the average grain size in the longitudinal direction is not less than 400 μm. The content of the element Zn in the composite layer is not less than 0.7% by weight after diffusion and volatilization during brazing. At the same time, the stress caused by stretching is eliminated and its toughness is increased.

[0027] Beneficial effects of the present invention: The aluminum alloy composite material prepared by the method of the present invention has strong corrosion resistance, large internal grains, good weldability, uniform brazing and long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 , Figure 4 The grain detection result and metallographic diagram of the sample of Example A;

[0029] Figure 2 , Figure 5 The grain detection result and metallographic diagram of the sample of Example B;

[0030] Figure 3 , Figure 6 The grain detection result and metallographic diagram of the sample of Example C;

[0031] Figure 7 , Figure 8It is a test chart of the zinc content of the outer composite layer and the inner composite layer in the embodiment. DETAILED DESCRIPTION

[0032] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The embodiments are only used to explain the present invention and do not limit the scope of protection.

[0033] An aluminum alloy composite material, wherein the alloy of the core material comprises: 0.3 weight % Cu, 0.8 weight % Mn, 0.05 weight % Ti, the weight % of Si and Fe is not higher than 0.5, the content of a single element is ≤0.05 weight % and the total content is ≤0.15 weight % of other elements, and the balance is aluminum; and the alloy of the composite layer comprises: 6.8 weight % Si, 0.8 weight % Zn, <0.3 weight % Fe, <0.15 weight % Cu, the content of a single element is ≤0.05 weight % of other elements, and the balance is aluminum.

[0034] The preparation method of the above aluminum alloy composite material comprises the following specific steps:

[0035] Step 1: Take the traditional aluminum ingot and melt it to obtain the core material ingot, and then saw it into shape;

[0036] Step 2: Heat treat the finished product of step 1, and then mill the surface to obtain a preliminary aluminum product;

[0037] Step 3: Take the aluminum product in step 2 and add two layers of composite plates for compounding, hot rolling and cold rolling, and make a coil of specified specifications;

[0038] Step 4: annealing the coil in step 3;

[0039] Step 5: Stretch the coiled material in step 4, the deformation of the first stretching is controlled at 1.5-2.5%, then place it for the second stretching, the deformation of the second stretching is controlled at 2.5-3.5%, and the total stretching deformation is controlled at 4-5%.

[0040] Step 6: Anneal the coiled material in step 5 at a temperature of 150-200°C, and cut and shape the coiled material after cooling.

[0041] The product obtained above was divided into three sections, A, B, and C, at the front, middle, and back, and its mechanical properties were tested, as shown in Table 1.

[0042] Table 1

[0043] Serial number Rm / Mpa Rp0.2 / Mpa A50 / ％ Cupping value / mm A 146 97 24 7.8 B 146 98 24.7 7.9 C 145 98 24.3 7.8

[0044] The performance of these three materials from the same batch not only meets the requirements for use in automotive heat exchangers, but the overall material is also relatively uniform.

[0045] The thickness of the three samples was tested, and 4 points were selected for each sample. The results are shown in Table 2.

[0046] Table 2

[0047]

[0048] According to this table, it can be seen that the overall thickness difference of the material after stretching is relatively uniform.

[0049] According to the national standard, the grain size of the three samples before and after brazing was tested, as shown in Table 3. The grain pictures refer to Figure 1-6 .

[0050] Table 3

[0051] Serial number Average grain size before welding μm Average grain size after welding μm A 30.6 627.02 B 28.19 634.26 C 31.73 720

[0052] Figure 1 ,It can be seen that the average grain size of the sample in section A before welding is 30.6μm. According to the metallographic diagram, it can be seen that the grains are uniform and there are no impurity compounds.

[0053] Figure 2 ,It can be seen that the average grain size of sample B before welding is 28.19μm, and the grains are uniform and free of impurities.

[0054] Figure 3 ,It can be seen that the average grain size of sample C before welding is 31.73μm, and the grains are uniform and free of impurities.

[0055] Figure 4 ,It can be seen that the average grain size of the sample in section A after welding is 627.02μm, and the grains are uniform and free of impurities.

[0056] Figure 5 ,It can be seen that the average grain size of sample B after welding is 634.26μm, and the grains are uniform and free of impurities.

[0057] Figure 6 ,It can be seen that the average grain size of sample C after welding is 720μm, and the grains are uniform and free of impurities.

[0058] Figure 7 and Figure 8 The Zn content test results of the inner and outer composite layers and the inner composite layer after welding are shown in Figure 7 and Figure 8 , the zinc content is 0.71 and 0.76. It can be seen that the Zn content of the sample after welding is greater than 0.7%.

[0059] According to the above test data, it can be understood that the aluminum alloy composite material prepared by the method of this embodiment has stable mechanical properties, uniform thickness, an average grain size before welding of 28.19-31.73 μm, fine and uniform grains, and is easy to stamp. The average grain size after welding is 627.02-720 μm, which is easy to weld and has good corrosion resistance.

Claims

1. An aluminum alloy composite material, characterized in that: The material of the aluminum alloy composite material is a multi-layer composite material, the multi-layer composite material comprises a core material and a composite layer, and the alloy of the core material comprises (mass fraction): 0.3-0.6% Cu, 0.8-1.5% Mn, 0.05-0.25% Ti, The mass ratio of Si to Fe is not higher than 0.5%, The mass fraction of a single element is ≤0.05% and the mass fraction of other elements is ≤0.15%, the balance being aluminum; The alloy of the composite layer comprises (mass fraction): 6.8-8.2% Si, 0.8-1.2% Zn, <0.3% Fe, <0.15% Cu, Other elements with a single element content of ≤ 0.05%, the balance being aluminum; of which: The content of Zn in the composite layer after diffusion and volatilization during brazing is not less than 0.7%; The average grain size of the aluminum alloy composite material in the longitudinal direction after brazing is not less than 400 μm.

2. The aluminum alloy composite material according to claim 1, characterized in that: The composite layer comprises an outer composite layer located on the outer surface of the core material and an inner composite layer located on the inner surface of the core material.

3. The aluminum alloy composite material according to claim 1 or 2, characterized in that: The thickness of the outer composite layer and the inner composite layer are respectively 8% and 10% of the thickness of the multi-layer composite material.

4. A method for preparing the aluminum alloy composite material according to any one of claims 1 to 3, wherein: The method comprises the following steps: Step 1: Take the traditional aluminum ingot and melt it to obtain the core material ingot, and then saw it into shape; Step 2: Heat treat the finished product of step 1, and then mill the surface to obtain a preliminary aluminum product; Step 3: Take the aluminum product in step 2 and add two layers of composite plates for compounding, hot rolling and cold rolling, and make a coil of specified specifications; Step 4: annealing the coil in step 3; Step 5: stretch the coiled material in step 4, control the deformation of the first stretching to be 1.5-2.5%, then place it for a second stretching, and control the deformation of the second stretching to be 2.5-3.5%; Step 6: Anneal the coiled material in step 5 at a temperature of 150-200°C, and cut and shape the coiled material after cooling.

5. The method for preparing the aluminum alloy composite material according to claim 4, characterized in that: In step 5, the total tensile deformation is controlled at 4-5%.

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