Effect of Welding Parameters and Tool pin features on Mechanical Properties of Dissimilar Aluminum Alloy Friction Stir Welds

The present work describes the effect of welding parameters and tool pin features during friction stir welding of dissimilar AA6082 and AA7050. Mechanical behaviour of dissimilar joints fabricated by using two distinct tool pin features, welding speed (WS), and rotary speed (RS) were compared for superior weld properties. All joints fabricated from tool having threaded cylindrical (TC) pin feature were defect-free, whereas welds fabricated by the plain cylindrical (PC) pin tool at 800 rpm RS using different WS were found defective. At the same RS and WS parameters combinations, the width of the softened region was found comparatively less in PC tool welds. The highest ultimate tensile strength (UTS) and elongation of 187.33 MPa and 7.55% were obtained for weld fabricated from TC tool at 180 mm.min(-1) WS and 800 rpm RS. However, the highest yield strength (YS) value of 168.8 MPa was obtained for dissimilar joints produced using the PC tool at 180 mm.min(-1) WS and 1600 rpm RS. The tensile specimens of defect-free dissimilar joints were fractured from respective minimum hardness locations in ductile mode.