Effect of copper donor material-assisted friction stir welding of AA6061-T6 alloy on downward force, microstructure, and mechanical properties

In this research, copper (Cu) donor material-assisted friction stir welding (FSW) of AA6061-T6 alloy was studied. Cu-assisted FSW joints were prepared at a constant tool rotational rate 1400 rpm and various speeds 1 mm/s 3 mm/s. The Cu material different thickness (i.e., 20%, 40%, 60%) with respect to the workpiece selected assist joining plunge stage. It is observed that downward force generated in process gradually decreased after introducing incremental thicknesses Post-weld analysis characterized terms microstructure mechanical properties. results zone (SZ) show formation finer grains due dynamic recrystallization plastic deformation. Micro-hardness tests reveal hardness from base metal (BM) SZ across heat-affected (HAZ) thermo-mechanically affected (TMAZ). lowest value appeared TMAZ HAZ where tensile failure occurs. With increasing speed, average lower heat input faster cooling rate. Tensile test plots no significant change ultimate strength or without material. Fractography tested samples shows both ductile brittle like structure for given parameters. This proposed work promising increase life decrement downforce during throughout Meanwhile, inclusion did not compromise weld quality properties micro-hardness.