飞秒激光对镍基合金的损伤机制和阈值行为

Femtoseoncd Laser-Induced Ablation Regimes and Thresholds in a Nickel-Based Superalloy

针对飞秒激光加工镍基单晶高温合金材料,在能量密度为0-12.8J/cm2和脉冲个数为0-8000范围内,对表面损伤和加工侧壁区域进行了显微形貌分析,研究了不同能量密度和脉冲个数情况下的损伤机制,不同损伤机制的损伤阈值和热效应。镍基单晶高温合金经飞秒激光加工后,呈现两种损伤机制,分别为非热熔性损伤和热熔性损伤,单脉冲损伤阈值分别为0.23J/cm2和1.21J/cm2,孕育系数分别为0.90和0.92。在此基础上,建立了损伤机制和损伤阈值与能量密度和脉冲个数的定量关系,实验结果对加工无微裂纹和无再铸层的高质量镍基航空器件的工艺选择有实际指导意义。

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/cm^2 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/cm^2 and 1.21 J/cm^2 in the superaUoy. 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.