Femtosecond Laser Removal Threshold of GH4099 Alloy

Surface material removal processing of GH4099 alloy plate was carried out by 500 fs femtosecond laser, and the effect of laser power on the morphology, micro-component and diameter of the material removal region was studied. The laser power and removal area diamenter was linearly fitted by least square method, and the removal threshold of the alloy was determined. The results show that when the laser power was not higher than 1.911 3 W, GH4099 alloy showed one removal area A having the same morphology and composition as the substrate, when the laser power was higher than 1.911 3 W, area B having melting-solidification morphology was present in the center of area A, and had more C and O elements than the substrate. The material removal forms of areas A and B were electrostatic stripping and thermal evaporation, and the laser removal thresholds were 0.413, 12.9 J·cm^-2, respectively. The reasonable laser energy density of laser processing of GH4099 alloy was 0.413-12.9 J·cm^-2.