Ti6Al4V合金毫秒激光打孔重铸层的形成机制  

Formation Mechanism of Recast Layer in Millisecond Laser Drilling of Ti6A14V Alloys

作　　者：张廷忠[1,2] 张冲[1] 李晋[2] 张宏超[1] 陆健[1] 

机构地区：[1]南京理工大学理学院,江苏南京210094 [2]周口师范学院机械与电气工程学院,河南周口466001

出　　处：《光学学报》2017年第2期136-145,共10页Acta Optica Sinica

基　　金：国家自然科学基金(61405147);江苏省自然科学基金(BK20130751);江苏省普通高校研究生科研创新计划(KYLX_0341)

摘　　要：Ti6Al4V合金在毫秒激光打孔过程中,沿孔壁会形成严重影响成品性能的重铸层。考虑熔体受到的热学和力学等方面的影响,基于修改的流体力学方程和改进的水平集法,建立了激光打孔的固/液/气三相二维数值计算模型,在单脉冲能量为3J的条件下,对不同脉宽参数的激光打孔进行数值研究。运用后处理技术提取了打孔过程中重铸层的温度场、流场和厚度分布情况。结果表明,蒸发和喷溅是熔体排除的主要方式,重铸层是在热-力耦合作用下形成的。重铸层的厚度随激光脉宽的增大而增加,并呈现从孔口到孔底逐渐变薄的特征。During the process of millisecond laser drilling of Ti6A14V alloys, the recast layer forms along hole walls, which is a serious detriment to hole quality. In consideration of the thermal and mechanical parameters influencing melt and based on the modified equations of fluid mechanics and improved Level-Set method, a solid/ liquid/gas three-phase two dimensional numerical model is constructed used for laser drilling. The numerical investigation of laser drilling with different pulse widths and with single pulse energy of 3 J is conducted. The temperature field, flow field, and thickness distribution of recast layer during the drilling process are obtained by using the post-processing technology. The results indicate that molten liquid is discharged mainly by means of evaporation and ejection and the recast layer is formed under the coupling effect of heat and force. The recast layer thickness increases with the increment of laser pulse width, which possesses a characteristic of recast layer beeoming thin slowly from top hole to bottom hole.

关 键 词：激光技术 激光打孔 重铸层 水平集法 TI6AL4V合金 毫秒激光 

分 类 号：O437[机械工程—光学工程]