3D surface morphology and performance of TC17 processed by surface severe plastic deformation

Abstract

3D surface morphology and performance including roughness, microhardness and tribological performance of TC17 processed by high energy shot peening (HESP) were investigated in detail. The experimental results showed that the HESP processed surfaces of TC17 were predominantly characterized by peaks and valleys. Upon the increase of the air pressure, the surface roughness of the HESP processed TC17 increased linearly, whereas it increased firstly and then fluctuated with the prolonging of peening duration. A better wear resistance-lubrication performance synergy was obtained at an air pressure of 0.45 MPa and a peening duration of 30 min. Within a certain range, the microhardness in the surface layer of TC17 was increased (~30.8%) under the combined effect of grain refinement, high-density dislocations and compressive residual stress (CRS) induced by HESP. Furthermore, the increase in microhardness of the HESP processed TC17 effectively suppressed the increasing of surface roughness, and the higher surface roughness led to the worse surface flatness, resulting in the changes in the wear resistance and lubrication performance.