Improving the superelastic wear resistance of laser powder bed fusing (LPBF) Ni-rich NiTi alloys by mechanical training

Abstract

Superelastic NiTi alloys produced through laser powder bed fusion (LPBF) hold great promise in advancing wear-resistant transmission devices for aerospace and related applications. However, limited research on their wear behavior and strategies for enhancing wear resistance raises concerns about their future application prospects. In this study, a straightforward yet highly effective pre-strain treatment method is introduced, resulting in a nearly twofold improvement in the wear resistance of LPBF-fabricated NiTi alloys. This method prunes microstructure characteristics, influences the martensitic transformation process that improves cyclic compression superelasticity and transforms the distribution characteristics of adhesion stress acting on the indenter during wear processes, thereby effectively enhancing wear resistance. Additionally, the present study proposes an analytical model that establishes a link between superelastic metal cyclic compression characteristics and wear behaviors, providing insight into the wear characteristics, especially for adhesive wear patterns of superelastic metals including LPBF-fabricated NiTi alloys through analysis of cyclic compression curve. This research contributes to the fundamental understanding of wear resistance mechanisms in superelastic engineering materials and opens avenues for further optimization in related applications.