Microstructure and properties of dissimilar materials Cu/Ti lapped joint by friction stir welding

The lap joint of commercial purity titanium (TA2) and copper (T2) plates were successfully produced via friction stir welding technique,the macrostructure and microstructure of Cu/Ti lap interface were researched respectively. The mechanical properties of the joint were characterized by tensile shear tests as well. The results show that the defect-free lapwelds with well-formed surface and interface of joint were obtained when rotation speed and travel speed were 800 r/min,40 mm/min respectively. The interface of joint exhibited the typical bounded texture microstructure of Cu and Ti in the stir zone,and a region of swirling-like of bimetallic weld of TA2 titanium and T2 copper was formed. Moreover,mechanical interlock was formed in some parts of lap joint. A maximum failure load of 95% of the one of T2 copper was achieved, and the fracture location was located in the advancing side of copper, the fracture was the typical ductile fracture.