TEM characterization on microstructure of Ti–6Al–4V/Ag nanocomposite formed by friction stir processing
School of Engineering
Friction stir processing (FSP) was successfully employed to produce gradient multi-phase structured Ti–6Al–4V/Ag nanocomposite surface layer. Microstructural evolution of amorphous/nanocrystalline/nano-twin in the surface layer was characterized by TEM in detail. The formation of amorphous phase in the upper surface of stir zone (SZ) was attributed to mechanically driven amorphization caused by dislocation gliding plastic deformation and elements mixing process. The dislocation activities played a dominant role in causing the distortion of lattices and nanocrystallization. The plastic deformation via FSP was responsible for considerable dislocations pile-up and tangle in the potential deformation bands.