Study on the fretting wear performance and mechanism of GH4169 superalloy after various laser shock peening treatments

GH4169 nickel-based superalloy is often used in aero engines, it always suffer from complicated fretting wear behaviors in the service. To improve the fretting wear performance, laser shock peening (LSP) technology was selected in this paper, the fretting wear properties, and mechanism of GH4169 superalloy following treatments with high-energy LSP (HE-LSP), low-energy LSP (LE-LSP), and femtosecond LSP (FS-LSP) were studied. Under 7 N load, the wear rate of HE-LSP and FS-LSP decreases by 58.6 % and 26.2 % respectively, while the wear rate of LE-LSP increases by 25.9 %. Under 12 N load, the wear rate of HE-LSP and FS-LSP decreases by 42.9 % and 12.7 % respectively, while the wear rate of LE-LSP increases by 104.8 %. The wear rate of GH4169 superalloy decreases due to the interaction of surface hardening layer and debris accumulation layer. The increase in wear rate is due to the non-uniform ablative holes on the sample surface and microcracks in the matrix. After receiving the LSP treatment, GH4169's wear mechanism shifted from adhesive wear to abrasive wear. LSP treatments can prevent the formation of adhesive zone because of the formation of a hardened layer and debris, and the increasing in tangential stiffness of the material. The HE-LSP technology has the best effect on the wear resistance of GH4169, followed by the FS-LSP treatment, while the LE-LSP treatment reduces the wear resistance of GH4169.