.cu / Al Laminated Composites Combine The Mechanism And Interfacial Reaction

With the rapid development of industry and the progress of science and technology today, single material has failed to meet modern society in comprehensive performance requirements of products. Therefore, the use of dissimilar metal composite technology has been paid more and more attention and known by people for it's multi-functional. Using solid-phase process can compound Cu and Al, which has obviously difference performance, into a stable layered structure, Enables it simultaneously to have the low contact resistance, the high thermal conductivity, the high electric conductivity of copper as well as the economy, the anticorrosion and the nature light and so on characteristics of aluminum, and make it become a hot point in the research field of material sciences.In this study, Cu/Al bimetal sheets are made by cold roll bonding. The deformation of the rolling and compounding mechanism of solid-phase was researched. Effects of different cold rolling reduction rate on interface bonding were discussed. In addition, the interfacial reaction between Cu and Al, the growing regularity of intermetallic compounds and the influence on interface bonding performance in the heat treatment phase were analyzed. Diffusion kinetics equation under different cold rolling reduction rate and annealing conditions were established. Cold rolling reduction rate effect on intermetallic growth was discussed. The above mentioned has provided theoretical basis for the control of interface diffusion layer and the optimization of the rolling process parameters.The investigations show that split mechanism and embedded mechanism play an important role in compounding Cu/Al roll cladding. With the rolling reduction rate increasing, effective integration of area interface increased in the range of 55% to 75%, leading to high bounding strength. Continue to raise the rolling reduction rate will reduce its impact on the emergence of the number of active centers and the bounding strength of bimetal sheets.In addition, during heat treatment time, the first reaction product CuAl₂ is presumed, then followed by Cu₉Al₄, and finally generated CuAl. There have apparent recovery on plasticity of Cu/Al bimetal sheets at the beginning of the heat treatment, with the highest elongation of 67.57%, and the strongest tensile strength of 129MPa. However, with prolonging of the annealing time, the intermetallic compound layer growing thickness, which will lead to brittle fracture of the interface, and seriously affect the performance of Cu/Al bimetal sheets.According to the experimental data, incubation period and diffusion kinetics equation under different cold rolling reduction rate were established. It was found that, the effects of the change of rolling reduction rate were minimal at low temperature. When the temperature is above 400℃, the number of active centers generated by the change of rolling reduction rate have more obvious affect on the thickness of the diffusion layer. When the rolling reduction rate reaches 75%, the energy which the interface obtain is difficult to rupture the remaining oxide and produce new activation centers, so continue to increase the reduction rate will reduce to its influence on the diffusion layer.