Strength Characteristics of Copper / Aluminum Alloy Friction Welded Joint

The friction welding for copper and aluminum is useful to minimize the diffusion thickness at the interface between copper and aluminum. The minimization of diffusion thickness is required for maintaining the joint strength. Because brittle intermetallic compounds are formed at the friction weld interface between copper and aluminum. However, the effects of intermetallic compounds on joint strength characteristics have not fully been clarified. In this experiment, pure aluminum was used as a intermediate layer for the friction welding between copper and aluminum alloy. It is confirmed that the good tensile strength distribution could be observed in the radius direction of friction welded joint by selecting the appropriate welding conditions. However, the Charpy impact energy at friction weld interface became comparatively low values, and revealed a remarkable distribution in the radius direction. It was also confirmed that the Charpy impact energy distribution was due to the thickness of intermetallic compounds, such as CuAl2, CuAl and Cu9Al4. Especially, the formation of CuAl2 and Cu9Al4 reduced the Charpy impact energy at friction weld interface.