Study On Rolling Process And Microstructure And Properties Of Cu/Al-Zn Clad Strip

Copper/Aluminum clad sheet is a very promising laminated metal composite, which combines the specific electrical conductivity, high thermal conductivity, high strength of copper material, and the low density, excellent corrosion resistance, low cost of aluminum material. The clad sheet can be widely used within the light-weight, economical, high-performance development industries, such as aerospace, vehicles, equipment, electrical appliances and daily necessities, etc. This paper researched in the effect of rolling technology and the content of zinc on the microstructure and properties of Cu/Al-Zn clad strip which were fabricated by Synchronous Rolling and Asynchronous Rolling bonding.In this paper, study the effect of rolling methods, asynchronous speed ratio, reduction ratio and heat treatment temperature after rolling and zinc content on Cu/Al-Zn interface morphology, composite tape peeling strength, elongation rate and interface elements distribution by metallographic microscope, scanning electron microscope and tensile test machine. With this study, the following conclusions were achieved:(1)The comparison results of Cu/Al-Zn clad strip which were produced by asynchronous rolling and synchronous rolling with the same process turned out to be that the performance of asynchronous rolling composite compared to synchronous rolling can improve the composite tape peeling strength and improve the smoothness of the interface.(2) The larger asynchronous speed ratio promoted the diffusion of elements in the Cu/Al-Zn interface, and improved the Cu/Al-Zn thickness ratio of clad sheet, reduced the microhardness of clad sheet. The relationship between the asynchronous speed ratio and peeling strength is parabola relation, the peeling strength reached the maximum value of 17.2N/mmwhen the asynchronous speed ratio at 1.25.(3) With the increased of the reduction rate, the peeling strength of the composite belt will increase significantly, but the high reduction rate will damage the composite belt elongation. The diffusion of elements in the interface will promote with the increase of reduction rate. As the reduction rate increases, copper and aluminum zinc alloy side lateral deformation tends to synchronization.(4) The effect of annealing to the microstructure and phase transition is obvious. The diffusion of elements in the interface and the thickness of the intermetallic compound increased when the heat treating temperature increased from 250℃ to 450℃. As the increase of heat treating temperature the elongation rate would be promoted, but the temperature was too high will lead to interfacial cracking. The relationship between the heat treating temperature and peeling strength is parabola relation, the peeling strength reached the maximum value at 300℃ for an hour.(5) With the increased of zinc content, the peeling strength of Cu/Al-Zn clad strip had been promoted, zinc can improve the performance of the aluminum side, the copper and aluminum zinc side deformation tends to be more synchronous, the composite interface tends to be flat.(6) Increase the zinc content will reduce the plasticity of Cu/Al-Zn clad strip, the zinc content will reduce elongation rate of composite.(7) Zinc content facilitated the diffusion of Cu and Al elements at the interface, it making Cu/Al-Zn clad strip easy to achieve all-right bond strength in the system of heat treatment with relatively low bond strength. But adding zinc will promote the diffusion of Cu and Al elements but do not change the interface compounds.