The influence of tool rotational speed on microstructure and mechanical performance of dissimilar FSLW

Abstract

FSLW is a novel solid-sate joining process in aircraft assembly technology that has offered superior welding quality to the joining of aluminum alloy. Concerning the success of FSLW light metal alloys coupled with lower operating costs due to improved energy efficiency and virtual lack of a consumable has emphasized the need to examine AA 2024-T4 and AA 7075-T6 based on different tool rotational speeds (RSs). This research examined the three important determinants of FSLW: cross-section morphology, microstructure behavior, and mechanical performance (lap shear failure load and fracture location) to realize the quality and reasonable experiment of the welding technique. The cross-section of the lap joint is investigated in this experiment; it is evident that the maximum temperature is found in the stir zone, and the shape looks like a bowl type. Further, it is found that tool RS does not have an influence on the effective sheet thickness, but it influences the effective lap width. With the increased RS, the effective lap width increased first and then decreased. Concerning grain size analysis, the bigger grain size was observed in the heat-affected zone, and the smaller grain size was observed in the thermomechanical-affected zone. According to the mechanical performance analysis, the lap shear failure load increased and then reduced with increased RS.