Stationary shoulder tool in friction stir processing: a novel low heat input tooling system for magnesium alloy

Present work aims to propose a new and novel low heat input stationary shoulder friction stir processing (SSFSP) for grain refinement. It uses stationary shoulder and rotating probe tool, which generates low heat input and small temperature gradient across thickness of material. In this study, SSFSP was performed in 6.35 mm thick AZ31B magnesium alloy without use of external cooling. The homogenous grain refinement occurred throughout the thickness (top, middle, and bottom). Enhancement in hardness and ductility exhibited minimum anisotropy across the processing thickness. Furthermore, fractography confirmed the similar fracture modes with dimples and tear ridges in all tensile specimens across the thickness.