A study of wear behaviour of additively Manufactured Co-Cr-Mo alloy after shot peening process

This study investigates the effects of shot peening (SP) on the wear behavior of laser powder bed fusion (L-PBF) manufactured Co-Cr-Mo alloys in as-built and heat-treated (HT) conditions. SP significantly increased surface hardness, reaching 685 HV via sub-structural refinement and strain-induced gamma-to-epsilon martensitic transformation (63.04% ɛ-HCP in HT + SP), confirmed by XRD analysis. The results show that the transformation-induced plasticity (TRIP) effect and dynamic work-hardening provide superior wear resistance (4.95 × 10 −5 mm 3 /Nm) in the HT + SP condition. Furthermore, SP-induced surface reactivity facilitates the formation of protective tribo-oxide films, thereby transitioning the mechanism into a self-lubricating regime. Wear test findings demonstrate that SP enhances surface integrity and may eliminate the need for post-process heat treatment in industrial and biomedical applications.