Study On Heat Treatment Process And Interface In The Cold-rolled Copper-Aluminum Composite Strip Under Magnetic Feild

Layered metal composite material is formed by layers of different properties of the metal. Compared with alloy, the materials after the rational design of combination can be obtained overall performance, e.g. high strength, corrosion resistance, electrical conductivity, thermal conductivity, etc. and applied to the special requirements. Composites are the necessary basic materials for the development of modern industry, national defense and science and technology, have become an important dominant material.The property of the composite material is determined mainly by the interface of the combination. The cold-rolled composite plates are combined chiefly by the mechanical occlusion and physical diffusion, and the results are poor. In order to improve its bond strength and functional performance, subsequent heat treatment is an indispensable step of the process.In this paper, in the different heat treatment processes on copper and aluminum cold-rolled composite strip in magnetic field, there are different morphology of composites interface. To discuss the change of structure and intermetallic componds we use the metallographic and SEM. And to discuss the reasons for the different interface based on the theory of diffusion and thermodynamic. Comprehensive results show that:1. Compare aluminum grain morphology when the magnetic field exists or not, we discover that the grain distribution along the same direction when the external magnetic field be there, and block and small grain. Correlation analysis showed that the magnetic field through the magneto-crystalline anisotropy and magnetostriction to control the structure of the material, and can affect the phase transition temperature, which show that the magnetic field can affect the aluminum recrystallization.2. After heat treatment, the composite interface generates intermetallic compounds, and under different conditions of temperature and magnetic field, the interface has three intermetallic compounds, followed from the aluminum to the copper:Al2Cu, AlCu and Al4Cu9.3. In different temperatures and different magnetic field, the composite interface width changes. The higher the temperature, the more interface width; and with increasing magnetic field, the width change as a concave parabolic. There is thinnest interface and it is less than without a magnetic field. The best magnetic heat treatment system is285℃for20minutes and magnetic field strength of0.1T.4. In different heat treatment conditions make the different layers’width of the three intermetallic compounds, and their respective mechanical properties, Al2Cu has high hardness, poor plasticity, while Al4Cu9low strength and the plastic is slightly better, make the compound with different intensity. And shear properties decreased with increasing temperature, the most change is from107.76MPa to80.68MPa; while it first decreases with the magnetic field increase then increase in shear properties.