Assessment of the influence of FSSW parameters on shear strength of dissimilar materials joint (AA6061/AZ31B)

Due to their distinctive qualities, ultra-lightweight alloys like AA6061 and AZ31B find use in a variety of significant applications. However, they are challenging to fusion weld due to incompatible metallurgical properties that result in significant cooling stresses and solidification defects like hot cracking and porosity. To address the problems brought on by the fusion welding process, solid state technology is employed to combine various materials. The goal of this study is to pinpoint the impacts of friction stir spot welding process variables on shear fracture stress, including rotation speed, plunge rate, dwell period, and shoulder to pin diameter ratio. At a rotational speed of 1000 rpm, a plunge rate of 16 mm/min, a dwell time of 5 min, and a tool shoulder to pin diameter ratio of 2.5, the FSSW joint encounters a greater shear fracture strain. According to the hook height, width, and initiation point, an appropriate fracture load was discovered, which improved the mechanical and metallurgical qualities of the joints.