Effect of tool pin profile on the mechanical and microstructural properties of dissimilar friction stir welded AA5083-H111 and AA6061-T6 aluminium alloys

In this present study, dissimilar Friction Stir Welding (FSW) is performed between AA5083-H111 and AA6061-T6 aluminum alloys to find out the optimum tool pin profile that can produce strong weldments with less defects. The macrostructural and the mechanical properties of weldments were investigated to find out the best tool pin profile. The tool pin profiles that were used in the present investigation are Straight Square, Threaded Cylinder, and Tapered Cylinder. The microstructural analyses of various regions were observed using an optical microscope. The Universal Testing Machine was accustomed to investigate the tensile strength of the weldments, and the hardness studies were done on various zones along the transverse direction of the weld using Vickers microhardness machine. From the experimental results, it was discovered that the straight square pin showed greater hardness values of 101 Hv1 in the weld nugget zone and higher tensile strength of 187.47 MPa with maximum elongation of 8.5% in comparison to the others. The failure site is visible on the AA6061-T6 side at the heat affected zone of the weld.