飞秒激光加工镍钛合金的烧蚀阈值实验研究

利用飞秒激光微加工系统对镍钛合金的烧蚀阈值进行理论和试验研究。设计了不同功率和扫描速度下的镍钛合金多脉冲累积烧蚀实验,应用扫描电子显微镜观测并分析试件烧蚀区域的形貌特征,计算得到了不同扫描速度下的烧蚀阈值分别为2.02、2.40、3.04、5.46、15.44 J/cm²。然后分析了多脉冲的累计效应对镍钛合金烧蚀阈值的影响规律,结果表明:当有效脉冲个数小于220时,烧蚀阈值会随着有效脉冲个数的增加而快速减小。但当脉冲数大于220时,脉冲能量逐渐饱和,减小的趋势趋于平缓最终趋于稳定。最后通过对比分析热影响区产生的原因,得出扫描速度1.5 mm/s、激光平均功率0.8 W是相对最优的飞秒激光加工镍钛合金工艺参数。

Experimental study on ablation threshold of NiTi shape memory alloy specimen by femtosecond laser processing

Theoretical and experimental research on the ablation threshold of NiTi based shape memory alloy by using the femtosecond laser micromachining system multi-pulse cumulative ablation experiments is performed on NiTi shape memory alloy specimen with different powers and scanning speed.Then a scanning electron microscope is used to observe and analyze the morphological characteristics of the ablated area.The ablation threshold values at different scanning speeds were calculated as 2.02,2.40,3.04,5.46 and 15.44 J/cm2,respectively.Besides the influence of the cumulative effect of multiple pulses on the ablation threshold of nickel-titanium alloy was studied.The results show that when the number of effective pulses is less than 220,the ablation threshold of Niti alloy decreases rapidly with the increase of the effective pulse number.But when the number of pulses is greater than 220,the pulse energy is gradually saturated,and the decreasing trend tends to be gentle and eventually stable.Finally,by comparative analysis of the causes of heat-affected zones,the relatively optimal parameters for the femtosecond laser processing of NiTi alloy are as follows:the scanning speed is 1.5 mm/s,and the average laser power of 0.8 W.