The microstructure,mechanical properties and hardness of TIG welded joints made by TA15 titanium
alloy with and without ultrasonic impact were analyzed and tensile fracture surfaces of the joint were observed. Meantime,the fracture of welding joint was investigated. The results show that,after welding,microstructure of the weld zone and the heat affected zone are different from the parent metal,showing characteristics of weave structure. Microstructure of the parent metal and the joint changed a littie after ultrasonic impact. The tensile strength and the elongation percentage of the parent metal and the weld zone increased slightly. Before and after ultrasonic impact,the property of the tensile fracture surfaces of the parent metal and the weld zone are dimple type fracture. After ultrasonic impact,
the surface microhardness and the section microhardness are obviously increased.