热障涂层损伤机理的热力化耦合理论与表征方法

Thermalization Coupling Theory and Characterization Method of Damage Mechanism of Thermal Barrier Coatings

热障涂层(TBCs)是提高发动机服役温度最切实可行的办法,航空发动机推重比、可靠性、热效率的任何一点进步都将依赖于热障涂层技术的发展.剥落失效是制约国际热障涂层发展与应用的重要瓶颈,这一瓶颈在我国尤为突出,但目前人们对热障涂层剥落失效的热力化耦合本质机制理解还很不透彻,缺乏合适的理论模型与分析方法来分析和控制涂层的过早剥落.针对“剥落失效”制约TBCs发展与应用的瓶颈问题提炼出热障涂层损伤机理的热力化耦合理论与实验方法的关键科学问题.基于该科学问题进行了详细的评述,包括建立TBCs破坏机制分析的热力化耦合理论模型,发展考虑实际几何形状、真实微观结构、复杂服役环境与热力化耦合理论模型的有限元模拟方法,结合TBCs热力化耦合破坏实验的研究,分析TBCs高温氧化、CMAS腐蚀、冲蚀,以及三者共同作用的热力化耦合破坏机理,提炼出影响TBCs剥落失效的关键因素.在此基础上,发展TBCs关键性能的表征方法,并建立关键因素与TBCs材料、工艺之间的关联,指导TBCs的优化设计与安全应用.最后提出了未来的重点研究方向.

Thermal barrier coating is the most feasible way to improve the engine service temperature.Any progress in the thrust-to-weight ratio,reliability and thermal efficiency of aero-engine will depend on the development of thermal barrier coating technology.Spalling failure is the important bottleneck restricting the development and application of thermal barrier coating in the world,which is particularly prominent in China.However,the essential mechanism of spalling failure of thermal barrier coating is still poorly understood,and there is a lack of appropriate theoretical model and analysis method to analyze and control the premature spalling of coating.In this work,aimming at the bottleneck problem of“spalling failure”restricting the development and application of TBCs,the key scientific problem of thermal-chemical coupling theory and experimental method of thermal barrier coating damage mechanism was extracted.Based on the scientific problems,previous work is reviewed in detail including establishing TBCs failure mechanism analysis of chemo-thermo-mechanically coupling theory model and developing chemo-thermo-mechanically coupling theory model of finite element simulation method considering the actual microstructure,complex geometry shape,and real service environment.Combined with the study of TBCs thermal-chemical coupling failure experiment,the thermal-chemical coupling failure mechanism of TBCs under high temperature oxidation,CMAS corrosion,erosion and their combined action was analyzed,and the key factors affecting the spalling failure of TBCs were extracted.On this basis,the characterization method of TBCs key performance was developed,and the correlation between key factors and TBCs materials and processes was established to guide the optimal design and safe application of TBCs.Finally,the future research direction is proposed.