热循环下梯度热障涂层热氧化物生长的应力分析  

Numerical Analysis of Thermal Stress for Gradient Thermal Barrier Coatings Experienced Thermal Oxidation Growth Under Thermal Cycle

作　　者：黄孝庆[1] 黄护林[1] 

机构地区：[1]南京航空航天大学高新技术研究院,江苏南京210016

出　　处：《热加工工艺》2012年第6期88-92,共5页Hot Working Technology

基　　金：江苏高校优势学科建设工程资助项目

摘　　要：建立了一种预测多层复合梯度热障涂层热应力的理论模型,并通过有限元方法分析了梯度涂层分布指数n、热循环过程中热氧化物的生长对涂层热应力大小及分布的影响。结果表明,通过控制梯度涂层的成分分布指数可以显著降低热应力和改善应力分布。当n=1时,涂层热应力较小且变化平缓,结合性能优异。与双层非梯度涂层的热应力对比可知,功能梯度涂层能显著地缓和涂层系统的热应力和消除应力集中。另外,热循环过程中梯度热障涂层与基体界面附近生长的热氧化物急剧地提升了界面附近的热应力,复杂而又集中的热应力对梯度涂层有很大的破坏。同时采用了一种方法来抑制热氧化物的生长,结果显示该方法能较好地优化涂层的热应力和改善涂层质量。A multi-layer numerical model was proposed in order to predict the thermal stress of multi-layer gradient thermal barrier coating system （TBCs）. Based on the finite element method, the effects of compositional exponent and the thermal oxidation which grew in thermal cycling process on the thermal stress and the distribution of TBCs were investigated. The results show that it is feasible to mitigate thermal stress and to improve the stress distribution by controlling compositional exponent n of the coatings. When n=1, the thermal stress is low and gentle changes, and the coatings performance is excellent. Compared with non-gradient duplex coatings, functionally gradient coatings are able to alleviate the thermal stress and suppress stress concentration of TBCs significantly. In addition, under the thermal cycling process, the thermal growth oxidation locates in the interface of gradient coatings and the substrates dramatically enhance the interface thermal stress. Complex and concentrated thermal stress have a tremendous damage to the gradient coating system. So a method is proposed to prevent the growth of thermal oxide. The results demonstrate that the method could be contributed to optimize the thermal stress and improve the quality of the coatings.

关 键 词：热障涂层 热应力 梯度涂层 热生长氧化物 有限元法 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]