高隔热双陶瓷热障涂层的应力定向主动调控及长寿命服役机理

Lifetime of thermal barrier coatings (TBCs) is a key performance indicator for long-term stability of aerospace engines and gas turbines. At present, the TBC long-lifetime mainly depends on the design of ceramic overall structure. However, the gradient temperature service environment is not considered by the overall design, resulting in non-uniform stress evolution and failure. Therefore, based on revealing the stress evolution of TBC gradient thermal cycles, this study subtly combines the ceramic units with specific layered structure and sintering resistance performance for a macro-microscopic cross-scale, to realize the TBC stress active control and long-lifetime. The project intends to establish a high thermal insulation double-layer TBC strain rate release model by the virtual crack propagation technology, clarifying the stress evolution law and failure thresholds at different depth of ceramic layers. Construct a TBC directional control unit based on layer structure control and high temperature sintering stress evolution characteristics, and the stress of TBC system is actively controlled in the failure threshold by preparation unit matching. The TBC lifetime is characterized by the gradient thermal cyclic test, and the failure mode and long service mechanism is analyzed. The TBC active control design concept based on TBC preparation-sintering duration-stress evolution established in this project has the advantages of stress adaption with service environment, and provides new thoughts and data support for advanced high-efficiency aero engine and gas turbine lifetime extension.

热障涂层（TBC）寿命是航空发动机和燃气轮机长期稳定服役的关键性能指标。目前长寿命依赖于陶瓷层整体结构设计，然而整体设计未能充分兼顾梯度温度环境，导致应力非均匀演变进而诱发失效。因此，本项目在揭示TBC梯度热循环应力演变规律的基础上，巧妙地将具有特定层状结构及抗烧结性能的陶瓷单元进行宏/微观跨尺度复合，实现TBC的应力主动调控与长寿命服役。项目采用虚拟裂纹扩展技术建立高隔热双层TBC应变率释放模型，探明热循环过程陶瓷层的应力分布演化规律及不同深度失效阈值；基于层状结构控制与高温烧结应力演变特性构筑定向调控单元，通过单元匹配将TBC系统应力主动控制于失效阈值内；利用梯度热循环分析主动调控TBC的失效模式，揭示其长寿命服役机理。本项目提出基于TBC制备-烧结时长-应力演变规律的单元构筑及匹配设计理念，兼顾TBC应力演变与服役环境，为先进高效航空发动机和燃气轮机延寿设计提供新思路和数据支持。

热障涂层（TBC）寿命是航空发动机和燃气轮机长期稳定服役的关键性能指标。目前长寿命依赖于陶瓷层整体结构设计，然而整体设计未能充分兼顾梯度温度环境，导致应力非均匀演变进而诱发失效。项目基于热障涂层服役过程增寿关键问题，开展了如下研究内容：（1）研究了双陶瓷层梯度热循环条件下不同深度区域陶瓷层组织结构及力学性能，探明了双陶瓷TBC陶瓷层表面梯度热循环条件下的差别烧结规律及失效时La2Zr2O7/YSZ体系模量阈值，为高隔热长寿命双陶瓷TBC设计提供了理论及数据依据；（2）研究了不同烧结温度及时长条件下陶瓷层制备工艺-烧结条件-应力演变特征，基于陶瓷梯度烧结规律，利用喷涂距离控制成功构筑了不同喷涂初态单元TBC体系；（3）实现了基于双陶瓷TBC服役过程烧结规律的应力主动调控及长寿命设计，最终建立了面向TBC服役过程应力与环境自适应的主动调控延寿方法，明确了其长寿命服役机制。项目研究成果对发展先进燃气轮机和航空发动机具有重要理论价值和技术支撑。