Repair Welding of Defects in 2219 Al Alloy Friction Stir Welded Joints

The primary and secondary friction stir repair welding experiments had been untaken for the lack of penetration and cavity of 2219 aluminum alloy joints welded by friction stir welding. The results show that the original defects can be removed with proper welding process parameters and thus we can achieve joints with smooth appearance and good properties. But the area of joint softened zone is increased dramatically by the increase of repair welding times. The tensile properties of primary repaired joints are satisfactory and better than that of secondary repaired for both lack of penetration and cavity defects. In the original joints, fractures all are started in the defects which led to a low ductility. However, after repair, joints fractured show a ductile fracture character at the interface of heat-affected zone and thermal-mechanical affected zone in retreating side.