Effect of surface modification technology on mechanical properties and dry fretting wear behavior of Inconel 718 alloy fabricated by laser powder-based direct energy deposition

Ultrasonic nanocrystal surface modification (UNSM) technique was applied to Inconel 718 alloy fabricated by laser powder-based direct energy deposition (LP-DED). The main aim of this study is to improve the mechanical properties and fretting wear behavior. No significant difference in surface roughness between the polished and UNSM-treated samples was made on purpose to avoid the effect of surface roughness on fretting wear behavior. The hardness and residual stress of the polished samples were increased after UNSM technique. Dry fretting wear behavior was evaluated using a ball-on-disk configuration at 24 and 60 °C. The results showed that the fretting wear resistance of the polished samples at both temperatures was enhanced, whereas an increase in temperature further enhanced the fretting wear resistance. In addition, possible factors influencing the enhancement in fretting wear behavior after UNSM technique in terms of fretting wear mechanisms and potential application were discussed. [Display omitted] •UNSM technique was applied to Inconel 718 alloy fabricated by LP-DED.•Surface and mechanical properties improved by UNSM technique.•Nanocrystallization and surface plastic deformation confirmed after UNSM technique.•Dry fretting wear after UNSM technique at 24 °C significantly enhanced.•Similar dry fretting wear results were obtained at 60 °C after UNSM technique.