Effect of laser shock peening without coating on fretting wear behavior of GH4169 superalloy at high-temperature

Improving the high-temperature wear resistance of aero-engine components is critical. Laser shock peening without coating (LSPwC) seems to have more potential because of lower morphology changes and simpler processing compared with conventional laser shock peening (LSP) techniques. The influence of LSPwC process and test temperature on the fretting wear behavior of GH4169 superalloy for 2 × 10⁵ cycles was investigated. The results indicate that a molten layer and a hardened layer are formed sequentially below the periodic dimple structure under the combination of shock wave and thermal effect. The formation of hardened layer enhances the difficulty of abrasive ploughing and the increase in test temperature promotes the generation of a glaze layer. Therefore, both LSPwC process and high temperature cause a reduction in wear volume. However, the main wear mechanism is similar before and after LSPwC. Besides, the protective mechanism of glaze layer under the gross slip regime may be ascribed to the frictional sintering process.