Femtoseoncd laser-induced ablation regimes and thresholds in a nickel-based superalloy

Femtosecond laser-induced ablation regimes and ablation thresholds of single-crystal nickel-based superalloy are investigated by means of microstructure on machined surface and trench as a function of laser fluence of 0~12.8 J/cm² and the number of pulses of 0~8000. Two distinct ablation regimes (no-melting and melting ablation regime) are observed, dependent on the incident laser fluence. The ablation threshold fluences for these two ablation regimes are determined to be 0.23 J/cm² and 1.21 J/cm² in the superalloy. And the incubation factors for these two ablation regimes are determined to be 0.90 and 0.92. Furthermore, the relationship between both ablation regimes and ablation thresholds and their parametric dependence is established. The experimental results have practical guiding for processing nickel-based aviation of no recast layer and micro-cracks.