Evaluation Of Material Damage And Comprehensive Quality In Trepan Drilling Of YSZ By Picosecond Pulsed Laser

Yttrium-stabilized-zirconia(YSZ)is widely used as the thermal barrier coating material in manufacturing of turbine blades.Due to its tendency to cause material damage and cracking,higher requirements are placed on the processing of film holes.Picosecond laser has become a research hotspot in the field of film hole drilling in recent years,due to its low thermal effect and non-selectivity to materials.In order to further explore the material damage of YSZ and the comprehensive quality evaluation of film holes,the following research work was carried out.Firstly,the phase change characteristics of YSZ are used as the entrance,and the material damage of YSZ is evaluated by the change of mechanical properties.Secondly,the mechanism of different drilling environments on YSZ materials is studied,and the most suitable one is selected to effectively control the material damage and cracks around the hole.Then,a simulation model for picosecond laser drilling on YSZ,based on phase transformation,is established,combined with the crack evaluation criteria to obtain stress-crack relationship and judge the generation of cracks.Finally,under the premise of effective cracking control,the laser parameters are effectively selected,to improve the comprehensively geometric quality of the holes.Through this research,the underwater drilling environment is selected,and the micro-holes with a diameter of 400?m are drilled on a 3mol% YSZ sheet with thickness of 0.5mm.The taper of the hole is 0.55°,and the roundness error is ?6%,with no obvious cracks around the hole.This research produces a high-quality processing method for ultra-fast laser drilling on TBC material and provides an effective control of material damage,which will improve the performance of turbine blade and promote the development of aircraft engine.