Processing Metal Matrix Composite (MMC) by FSP

Friction stir processing (FSP) uses the same principle as friction stir welding (FSW) [1]. In FSP a cylindrical tool that has a shoulder and a pin is rotated at high speed while a vertical force plunges the pin into the material. The frictional heat softens the material and as the tool is traversed forward the material is processed and consolidated. The process involves severe deformation and material mixing. The strain during FSP can go up to as high as 40 [2]. The temperature also rises significantly due to the frictional heating and the adiabatic heating arising from the deformation of the material [1]. The material mixing action and the thermomechanical aspect of the process thus offer the possibility of incorporating second phase particles in the stir zone (SZ) and make a composite.