Effect of Process Parameters on Microstructure Stability of FSW Butt Joints after Thermal Treatments

Friction Stir Welding process introduces a degree of deformation in the material that is related to process parameters. Rotational and transversal speeds directly regulate the heat input of welding process and then the morphology and microstructure characteristics. In the present work, mechanical properties and microstructure stability of FSW 6082T6 butt joints were investigated after exposure to high temperature or aging. The thermal stability of fine recrystallized grains in the nugget zone depends on process parameters and post-welding heat treatment. Ductility of post-welding heat treated FSW joints substantially increases with no loss in tensile strength. The micro hardness values of the whole joint are comparable. The effect of aging after cold deformation is also examined in FSW butt joints.