Mechanical and metallurgical characterization of friction stir welded AA2024 to pure copper using specific variables and positioning

A simple cylindrical pin shaped tool made economically of H13 tool steel was used to butt weld dissimilar metal plates of AA2024 and pure copper with friction stir welding with three different welding arrangements of plate positionings and tool offsets. Plunge depth, tool tilt angle and tool traverse speed remained steady while tool rotation speed varied in every arrangement. Tensile strength testing, microhardness testing, SEM, EDS and fractography were performed to evaluate the impact of plate positioning, tool offset and tool rotational speed on weld quality. The NZ showed swirl and vortex microstructures, and ductile fracture was identified as the cause of rupture in the FSWed samples. The arrangement AA2024 was placed in the advancing side without tool offset at tool rotation speed of 900 rpm demonstrated UTS, YS and microhardness as 198.98 MPa, 153.86 MPa and 251 HV respectively whereas maximum elongation, joint efficiency found 8.39%, 85.54% respectively.