Effect of Annealing Temperature on Bonding Properties of Cu/Al/Cu Clad Sheet

The Cu/Al/Cu 3 layers clad sheet was prepared by cold rolling method.The effect of annealing temperature on the bonding properties of Cu/Al/Cu clad sheet was studied.The microstructure of the interfacial transition layer was observed by optical microscope（OM）and scanning electron microscope（SEM）.The phase composition of the interface was analyzed by EDX and the bonding strength of the interface was measured by tensile test at room temperature.The results show that,the higher the annealing temperature is,the more obvious the interfacial diffusion layer is,and the larger the thickness of the diffusion layer is,the faster the growth rate is.With the increase of temperature,intermetallic compounds Cu9Al4,CuAl2and CuAl are formed at the intermetallic interface.When the annealing temperature reaches 550℃,it also produces Cu4Al3and Cu3Al2at the interface layer.The bonding strength of the interface increases first and then decreases with the increase of annealing temperature,and then tends to be stable.The optimum annealing temperature of Cu/Al/Cu clad sheet prepared by cold rolling method is 350℃.