Submerged friction stir processing (SFSP): An improved method for creating ultra-fine-grained bulk materials

This research demonstrates the use of submerged friction stir processing (SFSP) as an alternative and improved method for creating ultra-fine-grained bulk materials through severe plastic deformation. SFSP is compared with friction stir processing (FSP) done in air, through the use of thermocouples and transmission electron microscopy. Samples of Al-6061-T6 were created by SFSP that exhibit grain sizes less than 200 nm, while still obtaining a suitably stirred region.