热障涂层界面微区域热蠕变应力演化分析

热障涂层热循环载荷下不同界面层蠕变特性是影响界面微区域残余应力变化的关键因素,探究热障涂层蠕变与残余应力的关系有助于提高热障涂层的稳定性.以热弹塑蠕变理论为依据,采用Norton蠕变模型,建立陶瓷层、氧化层、粘接层和基体四层几何分析模型,考虑不同层蠕变和蠕变程度因素,研究热循环载荷作用下涂层界面微区域应力演化规律.结果表明,蠕变参数和蠕变层数的变化影响热障涂层界面残余应力的大小和分布,这对预测热障涂层失效具有指导意义.

ANALYSIS OF THERMAL CREEP STRESS EVOLUTION AROUND MICRO-INTERFACIAL REGIONS IN THERMAL BARRIER COATINGS

The creep property of different interfaces in thermal barrier coatings(TBCs) under thermal cyclic loads is a key factor affecting residual stress around micro-interfacial regions, and it contributes to improve TBCs’ stability to explore the relationship between creep and residual stress in TBCs. With the usage of Norton creep model, a four-layer geometric model, consisting of a ceramic layer, an oxide layer, an adhesive layer and a substrate, is established based on thermal elastic-plastic creep theory to study stress evolution law around micro-interfacial regions in TBCs under thermal cyclic loads, in which the number of creep layers and the creep levels are included. Results show that changes in creep parameters and the number of creep layers affect the magnitude and distribution of interfacial residual stress in TBCs, which is of guiding significance on failure prediction of TBCs.