Evaluation of high-temperature wear behaviour of selective laser melted 17-4 PH stainless steel through laser shock peening

Abstract

This study investigates the high-temperature wear resistance of laser shock peened (LSP) 17-4 precipitation-hardened stainless steel fabricated via selective laser melting (SLM), addressing the critical need for enhanced surface durability in elevated-temperature conditions. Four material conditions were analysed: as-printed (AP), heat-treated (AP + HT), laser shock peened (AP + LSP), and both treatments combined (AP + HT + LSP). Wear tests using a pin-on-disc setup were conducted at room temperature (RT), 150 °C, 250 °C, and 350 °C. The AP + LSP condition consistently exhibited the lowest wear, attributed to the introduction of compressive residual stresses, severe plastic deformation, and strain hardening. In contrast, AP + HT and AP + HT + LSP suffered higher wear due to oxidation-assisted delamination and brittle morphology. At RT and 350 °C, AP + LSP achieved 34 % and 17 % lower wear rates than AP + HT, respectively. These findings highlight the effectiveness of LSP in enhancing the high-temperature tribological performance of SLM 17-4 PH stainless steel and offer valuable insights for its deployment in aerospace and energy applications.