带热障涂层涡轮叶片气膜孔飞秒激光微纳跨尺度制备及孔壁侧隙自愈合修复

A higher requirements for film cooling hole has been proposed in the new generation of aircraft engine, and processing these film cooling holes with high quality and efficiency in thermal barrier coating coated aero-engines is becoming the key issue. Laser processing is now becoming a trend in hole precision-machining due to it incorporates such many unique advantages as high efficiency, controllable quality and performance, wide-processing capabilities, etc. Aiming at the theory and technology problem in film holes machining on TBCs coated blade, a new theory and method in laser micro-nano across scales processing based on self-healing repair of the sidewall pores is proposed. Firstly, the project focuses on the influence laws and suppression methods of plasma induced thermal damage, interface effect and the nonlinear effect in femtosecond laser processing of the ceramic layer. Secondly, it also explores the mechanism and technology in self-healing repair of pores in ceramic hole sidewall, and the influence factors as well as improving methods of wettability, bonding strength, high temperature performance of repairing structure. Lastly, this project further researches on the formation law, conditions and controllable synchronous induction of surface texture with self-cleaning function on film hole wall during femtosecond laser circular-machining shaping of holes. Finally, it is expected to achieve the goal of "no cracks on hole wall", "no pores on ceramic hole wall " and "self-cleaning and anti-erosion" film cooling holes with controllable quality and performance on TBCs coated turbine blade in femtosecond laser processing. Furthermore, the research results can provide the processing theory and technology support for film hole machining of our country' aviation turbine blade.

新一代航空发动机对气膜冷却孔质量提出了更高的要求，在带热障涂层叶片上高质高效加工气膜冷却孔成为亟待解决的关键技术问题。激光加工凭借高效率、可控质控性、加工对象广等独特优点，成为气膜孔精密加工的未来发展趋势。本项目针对带热障涂层涡轮叶片气膜孔激光加工的理论与技术难题，提出了一种基于孔壁侧隙自愈合修复的气膜孔飞秒激光微纳跨尺度加工的新理论与新方法。首先，研究飞秒激光加工陶瓷层时的等离子致热损伤、界面效应、非线性效应的影响规律与抑制方法；其次，探索陶瓷孔壁侧隙自愈合修复机理与工艺及修复组织浸润性、结合强度、高温性能的影响因素及改善方法；最后，研究飞秒激光环切成型气膜孔过程中具有自清洁功能孔壁表面织构的形成规律、产生条件及其可控同步诱导制备，最终实现“无裂纹”、“无陶瓷孔壁侧隙”及“自清洁自防蚀”带热障涂层涡轮叶片气膜孔飞秒激光控质控性加工，为我国航空涡轮叶片气膜冷却的加工奠定理论基础和技术支撑。

本项目针对带热障涂层涡轮叶片气膜孔激光加工的理论与技术难题，首先，探索了飞秒激光打孔过程等离子在空间和时间上的演变过程，研究了飞秒激光偏振态、光束调控及辅助气体压强对打孔质量的影响规律；其次，探索陶瓷孔壁侧隙自愈合修复机理与工艺，研究了自愈合粉末、飞秒激光、皮秒激光等对陶瓷孔侧隙修复工艺方法，高温腐蚀实验结果表明，经过修复的气膜孔可以显著提高其抗高温熔盐腐蚀性能；最后，研究了旋切圈数、扫描速度、离焦量、激光功率等多参量对加工质量的影响，确定了定量刻蚀工艺，通过调控激光偏振态加工实现了对孔壁表面织构的可控制备，分析了其微观结构特性以及形成原理，实现具有防腐防尘自清洁特性的气膜冷却孔控质控性加工。通过本项目的研究，掌握了一种基于孔壁侧隙自愈合修复的气膜孔飞秒激光微纳跨尺度加工的新理论与新方法，申请发明专利2项，发表SCI论文7篇。