Microstructural degradation control and dissimilar joint optimization through friction stir processing

The need for hybrid-welded joints has continued to increase in different industrial sectors. In this study, the effect of the friction stir welding process parameters on the microstructure and mechanical properties of hybrid aluminum-copper lap joint was investigated. The investigation focused on the impact of friction stir process on the mechanical characteristics, interface, and macro- and microstructure of base metals. A tool inserted from the copper side was subjected to two traveling speeds of 0.83 mm/s and 1.66 mm/s and three rotation speeds of 500, 1000, and1500 rpm. Friction stir processing at rotational speeds over 500 rpm forms the nugget zone with minimal interface flaws. Traveling speed of 1.66 mm/s shows defect free interface. At lower traveling speed and high rotational speed, worst welding interface occurred. At a travel speed of 1.66 mm/s and a rotation speed of 1500 rpm, the maximum tensile shear force was achieved.