Effect of ultrasonic vibration on welding load, macrostructure, and mechanical properties of Al/Mg alloy joints fabricated by friction stir lap welding

An initial study is proposed in order to evaluate the outcomes of ultrasonic vibration in friction stir welding of Al and Mg alloys for lap configuration. A novel ultrasonic assembly is designed and developed such that ultrasonic vibrations could be enforced along the welding direction into the weldment via the welding tool. Various sets of welding parameters are picked out for experimentation and thereafter optimum are evaluated. With ultrasonic assistance during pin and shoulder plunging, a substantial diminution in welding load, up to 30 and 19.75% are obtained while the noteworthy reduction in tool torque and input power is also perceived at optimum parameters. Additionally, lap shear tests result into an improvement of 37.88 and 39.24%, respectively, in context to failure load and weldment elongation. Macrostructure analysis portrays elimination of defects, enhanced material mixing, and broadening of the stirred zone with acoustic assistance.