飞秒激光能量密度对镍基合金重铸层和加工效率的影响

摘要

以航空发动机叶片制孔为导向,结合飞秒激光对单晶镍基高温合金材料的非热熔性损伤阈值(Φth1)和热熔性损伤阈值(Φth2)特征,研究了飞秒激光能量密度(0＜Φ＜44.2J/cm2)对制孔重铸层和加工效率的影响规律.研究结果表明:在Φth1＜Φ＜Φth22时,镍基合金经飞秒激光加工后加工侧壁没有出现明显的重铸物;在Φ＞Φth2时,加工侧壁开始出现重铸物,并随着能量密度的增加,重铸层厚度增大.在试验结果的基础上,建立了飞秒激光单脉冲加工深度与能量密度的定量关系.能量密度越高,飞秒激光单脉冲加工深度越大,加工效率越高.%The effect of femtosecond laser fluence (0＜Φ＜44.2J/cm2) on recast layer and machining efficiency were investigated with the no-melting ablation threshold (Φth1) and melting ablation threshold (Φth2) in a single-crystal nickelbased superalloy.For the laser fluence range (Φth1＜Φ＜Φth2),there are no indications of conventional laser-induced recast layers in laser-machined area of nickel-base superalloy.For the laser fluence Φ＞Φth2,recast layers appeared gradually and increased with increasing laser fluence.The relationship between ablation depth for single pulse and laser fluence is established.The larger ablation rate is associated with higher laser fluence.