Influence of the surface nanocrystallization on the gas nitriding of Ti–6Al–4V alloy

Supersonic Fine Particle Bombarding (SFPB) was performed on Ti–6Al–4V alloy to form surface nanostructures. The effect of the surface nanostructures on the gas nitriding was investigated by varying the nitriding temperature and time. Through SFPB process, a nanocrystalline surface layer with a mean grain size of 16 nm was obtained, presenting a high hardness of 640 HV. In comparison to the surface without SFPB treatment, the treated surface exhibited a thick nitrogen diffusion layer and high hardness under the same nitriding process.