Research on the mechanism of DD6 single crystal superalloy wear resistance improvement by femtosecond laser modification

The wear resistance of turbine blades tenon is critical to its fretting fatigue life. A method to improve the wear resistance of DD6 single crystal superalloy (DSCS) by femtosecond laser modification (FLM) is proposed. In this paper, the FLM was performed on the surface of DSCS under atmospheric condition without protective layer and confinement layer. The wear behavior after FLM at various laser energies (10, 100, and 240 μJ) was investigated. Results indicate that the wear resistance increases by about 25 % to 58 % after FLM, attributable to surface hardening layer and generation of wear debris layer by removal of asperity during the sliding wear. The formation of asperity and hardening layer is the combined effects of strong laser shock wave and slight ablation in the irradiated region. Finally, the femtosecond laser-affected region can be divided into oxide zone, severe deformed zone, and moderate deformed zone near the surface. Femtosecond laser provides a new possibility and method for wear resistance and friction reduction.