Characterization of surface layer in TC17 alloy treated by air blast shot peening

• A surface layer with smallest grain size of 6.7 nm is fabricated in TC17 alloy.
• The variation of nanocrystalline structure during shot peening is determined.
• The variation of surface roughness during shot peening is determined.
• The variation of the mass loss during shot peening is determined.

The air blast shot peening of TC17 alloy was carried out at the air pressures ranges from 0.15 MPa to 0.35 MPa and processing durations ranges from 5 min to 60 min. The effects of the air pressure and processing duration on the microstructure and surface roughness of TC17 alloy were investigated. The experimental results showed that the microstructure gradually changed from nanocrystalline structure in the surface layer to the undeformed grains in the base TC17 alloy. The nanostructured surface layer with equiaxed grains and smallest grain size of 6.7 nm was fabricated in base TC17 alloy. The grain size of nanostructured surface layer in the TC17 alloy decreased with an increase in the air pressure and processing duration. Meanwhile, the results indicated an increasing surface roughness and a decreasing mass of the TC17 alloy specimens with an increase in the air pressure and processing duration due to the air blast shot peening treatment.