多次热循环下热障涂层热稳定过程的数值模拟

Numerical Simulation of the Stabilization in Thermal Barrier Coatings During Thermal Cycling

采用热弹塑性有限元方法,通过对热障涂层多次热循环降温过程中产生的残余应力的数值模拟,研究了在热梯度、热膨胀失调情况下涂层的热稳定过程。结果表明,在相同材料参数情况下,陶瓷层与粘接层的界面形貌对残余应力及稳定状态有显著的影响,凹凸不平的界面将会使界面残余应力发生突变,不利于增强界面结合强度和涂层结构的稳定。该结果对分析涂层寿命及失效机制有指导意义。

The residual stress accumulation during thermal cycling of thermal barrier coatings （TBCs） was simulated by thermal elastic-plastic finite element method in this paper. Stabilization process of thermal barrier coatings during thermal cycling was studied when considered of materials thermal gradient and thermal expansion misfit. And the influences of the interfacial topography on residual stress and stabilization process were analyzed. The results show that the residual stress and stabilization process are affected remarkably by interfacial topography between top coating and bond coating. Accidented interface will cause the sudden change of the interfacial residual stress which is bad to the interface bondingstrength and the stabilization. The results are useful to study the life and the mechanism of final spallation of TBCs.