Effects of Friction Stir Processing on Mechanical Properties of the Cast Aluminum Alloy A356

Surfaces of A356 castings were treated by friction stir processing to reduce porosity and to create more uniform distributions of second-phase particles. Dendritic microstructures were eliminated in stir zones. The ultimate tensile strength, ductility, and fatigue life of the cast A356 was increased by friction stir processing. Tensile specimens of cast and friction stir processed metal were also given a T7 heat treatment. Higher tensile strengths and ductilities were also measured for these friction stir processed specimens.