Tribological behavior of nanosecond laser-textured leaded Ni-rich NiTi shape mamory alloy fabricated by laser powder bed fusion

Abstract

NiTi alloys with pseudoelastic properties at room temperature were fabricated by laser powder bed fusion (LPBF) processes. The tribological behavior of nanosecond laser-textured leaded LPBF-fabricated NiTi alloys under dry conditions was investigated. The results showed that the reduction in friction coefficient were derived from the fabrication of the bionic tree frog toe end structure formed by nanosecond laser compared with the un-textured surface. The synergetic effects of pseudoelastic properties of LPBF-fabricated NiTi alloys and nanosecond laser surface texturing (LST) on the tribological performances were investigated in detail. The maximum rate of decrease of friction coefficient was 82% when the textured area density was 54.7% and then the mechanism of wear reduction was further studied. Experimental results indicated that the formation of tribo-oxide layers was critical for increasing friction reduction and wear resistance. The implementation of biomimetic hexagonal micro-textures on the surface of LPBF-fabricated NiTi alloy exhibited excellent wear resistance.