Ultrasonic spot welding of aluminum alloys: A review

As a solid joining technique, ultrasonic spot welding is a promising spot welding process to fabricate the aluminum alloy joints. This paper summarizes the current state of joining aluminum alloy by ultrasonic spot welding with numerous critical issues, such as general process parameters, materials flow, interfacial temperature, interfacial shear force, stress distribution, relative motion, strengthening mechanism, macrostructure, microstructure and mechanical properties. Meanwhile future trends in the field are pointed out.