Nanostructure and surface roughness in the processed surface layer of Ti-6Al-4V via shot peening

Shot peening process of Ti-6Al-4V was performed at the air pressures ranging from 0.15 MPa to 0.35 MPa and processing durations ranging from 15 min to 60 min so as to obtain the effects of the shot peening on the structure characteristic and surface roughness of Ti-6Al-4V. The experimental results showed that the nanocrystalline layer in Ti-6Al-4V could be fabricated via shot peening at the air pressure above 0.25 MPa and the processing duration above 30 min. The thickness of deformation layer and the degree of grain refinement increased with an increase in the air pressure and processing duration, but the corresponding surface became rougher. In order to obtain a good combination between the grain refinement and the surface roughness, shot peening of Ti-6Al-4V should be performed at a smaller air pressure and a longer processing duration.