Abstract

Friction stir welding (FSW) joins the material in solid state, and it gets evolved as a new and effective technique to join dissimilar materials such as aluminum and copper. FSW tool design and configuration critically affect the joint quality. This study has evaluated the effect of different pin profiles used during FSW of AA5754 Al alloy and commercially pure copper in a butt configuration on the microstructure, material movement, and microhardness for the different joints. The joining is performed through the different pin profiles of cylindrical, taper, cylindrical cam, taper cam, and square shape at the rotational and welding speed of 900 rpm and 40 mm/min respectively. Among all joints, the square pin profile provides good joining and microhardness. Square tool pin profile facilitates good amount of mixing at nugget zone, which consequently increases the hardness. The material movement in square tool pin profile joint is also studied on the longitudinal plane to understand the effect of pulsating and stirring action on the material mixing pattern in dissimilar FSW. It is evident that the softer material in the stir zone gets more stirring, and the flow lines are clearly visible for the stirred material.