高温合金不同脉宽超快激光作用下多脉冲去除阈值

实验研究了激光脉冲宽度和脉冲个数对镍基高温合金材料去除阈值的影响，分别在290 fs，1 ps和7 ps脉宽的激光下，使用1，10，50，100，300，500和1000个不同能量的激光脉冲辐照高温合金样品表面。实验结果表明，烧蚀坑尺寸会随脉冲数的增加而增加，而脉冲宽度的增加会加大脉冲个数对烧蚀坑直径的影响。通过烧蚀坑直径的平方值与激光脉冲能量之间存在的对数关系，得到了不同脉冲宽度下镍基高温合金的多脉冲材料阈值。3种不同脉宽下的高温合金多脉冲去除阈值都存在显著的累积效应。根据去除阈值计算得到290 fs，1 ps和7 ps脉宽下的累积效应系数分别为0.88，0.86和0.78。

Multi-pulses ablation threshold of Ni-based superalloy irradiated by ultrafast laser with different pulse duration

The effects of the laser pulse duration and the number of pulses on the ablation threshold of Ni-based superalloy were experimentally investigated. In this experiment, Ni-based superalloy samples were irradiated by 1, 10, 50, 100, 300, 500 and 1000 laser pulses with different pulse duration, respectively, and pulse duration 290 fs, 1 ps and 7 ps were explored. The diameter of ablation holes expands with the increase of laser pulse and the effect of pulse number on the diameter of ablation holes increases with the pulse duration from the experiments. By analyzing the relationship between the diameter of ablation holes and laser pulse energy, multi-pulse ablation threshold of Ni-based superalloy irradiated by ultrafast laser with different pulse duration can be obtained. No matter what the pulse duration of the laser was, the incubation effects of multi-pulse irradiation on the surface of the superalloy were significant. And the incubation coefficient for the thresholds calculated by diameter respectively in 290 fs, 1 ps, and 7 ps is fitted to be 0.88, 0.86 and 0.78.