CMAS高温腐蚀下热障涂层热力化耦合的早期失效分析

Thermal barrier coatings (TBCs), the most reliable resolution to improve the service temperature of aeroengines, have been developed as a key technique and an important indicator of the scientific and technological level of a country. However, TBCs are unavoidable impacted by CMAS high temperature corrosion during flight, and result in premature spallation of coatings, which has been proved to be the most dangerous failure type by the production and application departments. Neverthness, the failure mechanism of TBCs attacked by CMAS high temperature corrosion is still unclear, and there is lack of a suitable method to analyze and control the premature spallation of coatings. The purpose of this project is to understand the CMAS corrosion mechnisam, extract the key factors of affecting premature spallation of coatings during CMAS corrosion, and then guide the design, preparation and application of TBCs. Starting from the original failure behavior of TBCs subjected to CMAS high temperature corrosion, the thermo-chemo- mechanically coupled deformation feature will be analyzed during the original CMAS high temperature corrosion stage. Based on deformation feature, the stress field during original thermo-chemo- mechanically coupled failure will be analyzed by establishing a suitable model, and the key parameters resulting in CMAS corrosion will be determined. This will provide a guidance for the optimization and application of TBCs.

作为目前提高发动机服役温度最切实可行的办法，热障涂层技术已被世界各国列为航空发动机的三大关键技术(定向高温单晶、冷却)之一，成为衡量一个国家工业和科技发展水平的重要标志。然而，TBCs在飞机飞行过程中将不可避免的受到高温CMAS腐蚀作用，从而发生过早剥落，这一失效已被TBCs生产与应用部门证实是最危险的失效形式，但目前人们对TBCs高温CMAS腐蚀失效机制的理解还很不透彻，缺乏合适的方法来分析和控制涂层的过早剥落。本申请项目以"理解TBCs高温CMAS腐蚀失效的机理，提炼影响CMAS腐蚀时涂层过早剥落的关键因素，指导TBCs的设计制备与安全应用"为目标，从TBCs高温CMAS腐蚀的最早期失效行为开始，分析TBCs热力化耦合的局部变形规律，以此为基础建立早期热力化耦合应力场的分析模型，提炼出影响TBCs高温CMAS腐蚀失效的关键因素，为抗CMAS腐蚀TBCs的设计制备提供指导。

热障涂层(Thermal Barrier Coatings，TBCs)因为耐高温、高隔热、抗腐蚀等优异性能，已成为航空发动机涡轮叶片等热端部件不可缺少的热防护材料。然而，在含有杂质颗粒的高温、高速燃气环境下服役时，不可避免的会受到钙镁铝硅等金属氧化物的混合物（简称CMAS）腐蚀，引起涂层结构、性质、成分的变化并迅速导致涂层剥落失效，这一失效被证实是涂层剥落最危险的形式。但前期工作对于在热、力、化多场耦合作用下CMAS高温腐蚀的机制的理解并不透彻，对于影响CMAS腐蚀时涂层剥落的关键因素的提炼并不完全，对于如何控制涂层过早剥落的方法并不清晰。本项目以“理解TBCs高温CMAS腐蚀失效的机理，提炼决定腐蚀失效的关键因素”为目标，开展了CMAS高温腐蚀下TBCs热力化耦合的早期失效实验研究，观测并分析了CMAS早期热力化耦合失效时涂层的局部変形规律，建立了早期热力化耦合失效的应力场分析模型，提炼了决定TBCs高温CMAS腐蚀失效的关键因素，并建立了CMAS腐蚀机制图。为TBCs的优化设计及其在航空发动机的安全应用提供指导。