Investigation of the optimal parameters for butt joints in a friction stir welding (FSW) process with dissimilar aluminium alloys

Abstract

Aluminum alloys are used in the modern automotive industry because they are lightweight. However, it is establised that conventional fusion welding processes affect weld performance. In this study, friction stir welding (FSW), also known as solid-state welding, was used to weld dissimilar aluminum alloys, AA6061-T6 and AA5083 plates. Response surface methodology based on Box-Behnken design (BBD) was used to investigate the appropriate process parameters. In this study, the effects of rotation speed (S), welding feed rate (f), and work angle (θ) were investigated. These three factors were examined at three levels over 17 experimental runs. The design was used to conduct experiments and develop mathematical regression models. Variance analysis was performed to examine the adequacy of the developed models. Finally, the effects of the process parameters on the mechanical properties of welded alloyes were investigated using mathematical models based on the macrostructure, microstructure, chemical composition, and fracture characteristics of the joints using SEM. The investigation found that the optimum welding parameters are a rotational speed of 777 rpm, welding speed of 44 mm min−1, and a work angle of 0.75°. Furthermore, the results confirm that the mathematical models and experiments are consistent.