Effect of weld parameters on the microstructure and mechanical properties of dissimilar friction stir joints between pure copper and the aluminum alloy AA7075 T6

Friction stir welding frequently produces a superior microstructure and mechanical properties than conventional methods for welding nonferrous materials and alloys. In this study, friction stir welding was used to join sheets of the aluminum alloy AA7075 with commercially pure copper cpCu. Two rotational speeds, 660 and 920 rpm, and three welding speeds, 18, 32 and 54 mm x min(-1), were studied to determine the effects of these parameters on the structure and mechanical properties of friction stir welded AA7075-cpCu. The joint performance was investigated by conducting optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), by microhardness measurements and mechanical testing (e. g. tensile tests). A maximum tensile strength of 224 MPa and percentage elongation of 2.49 were obtained when friction stir welding process parameters, namely rotational speed and welding speed, were kept at 660 rpm and 32 mm x min(-1), respectively.