摘要
针对目前带热障涂层(TBC)叶片的难加工问题,开展了皮秒激光加工热障涂层的试验。试验分别在三种扫描速度下(50 mm/s,150 mm/s,250 mm/s)使用不同单脉冲能量加工热障涂层。发现随着扫描速度的增大,材料出现缺陷对应的最小单脉冲能量分别为120μs,280μs和400μs;随着脉冲能量的增大,热障涂层出现裂纹、崩边及脱落等缺陷越多。通过面积外延法,计算三种扫描速度下多脉冲烧蚀阈值分别为1.17 J/cm^2、2.72 J/cm^2和4.45 J/cm^2,随着激光扫描速度的提高,烧蚀阈值也随之增大。小脉冲能量去除热障涂层主要以雪崩电离为主,当以较大脉冲能量去除时主要以多光子吸收为主,当脉冲能量远大于烧蚀阈值时会在加工区域产生烧蚀潜热,在材料加工区域边缘处因产生应力集中出现微裂纹、崩块和整块脱落的缺陷。
For the problem of remove with thermal barrier coating(TBC)at present,the picosecond laser machining thermal barrier coating has been studied.The separation ablation experiment is carried out with different laser scanning speed(50mm/s,150mm/s,250mm/s).With the increase of scanning speed,the material destroyed of minimum single pulse energy are 120,280and 400.With the increase of pulse energy,the defects such as crack,edge collapse and shedding increase.The multi pulse ablation thresholdare 1.17J/cm^2、2.72J/cm^2 and 4.45J/cm^2 of three speeds by the straightline fitting method.With the increase of scanning speed,the pulse ablation threshold also increase.The TBC removed is main avalanche ionization by small pulse energy and removed is multiphoton absorption by large pulse energy.When the pulse energy far greater than the ablation threshold,the processing area has ablative latent heat.There are crack,edge collapse and shedding in the hole wall because of the residual stress.
作者
毛忠
张晓兵
李元成
张伟
蔡敏
纪亮
Mao Zhong;Zhang Xiaobing;Li Yuanchen;Zhang Wei;Cai Min;Ji Liang(AVIC Manufacturing Technology Institute,National Key Laboratory of Science and Technology on Power Beam Process,Beijing100024,China)
出处
《应用激光》
CSCD
北大核心
2020年第1期79-85,共7页
Applied Laser
关键词
热障涂层
皮秒激光
脉冲能量
扫描速度
烧蚀阈值
thermal barrier coatings
picosecond laser
laser pulse energy
scanningspeed
ablation threshold
