Mechanical and Microstructural Behavior of Dissimilar AA2014-T6 and AA7075-T6 Aluminium Alloys Joined by Friction Stir Welding

The present work aims to investigate the mechanical and microstructural properties of dissimilar welding of 2014-T6 and 7075-T6 aluminium alloys of 6 mm thick sheets, using butt welded friction stir welding. The two distinct materials welded with the perpendicular to the rolling direction of the dissimilar weld zone. The welded joint was tested in tension at room temperature to investigate the mechanical response and also to observe the differences with the parent materials. The diversity in the properties across the weld and its material mixing behavior have considered by resolving the thermal cycle, hardness test, and microstructural analysis. Plastic deformation along with recrystallization during the welding process resulted in the formation of distinct zones which could be identified by their respective microstructures. SEM/EDS analysis was carried out to analysis the precipitates, which influenced the properties of the joints. Based on the present study, 840 rpm with 30 mm/min weld speed seemed to be optimum.