摘要
热障涂层在高温热循环的服役环境中会出现性能退化,最终剥离失效.本文以等离子喷涂的YSZ涂层为研究对象,基于亚临界裂纹扩展模型,引入临界能量释放率指数模型,结合改进的热生长氧化层增厚模型,推导了涂层循环失效预测模型.通过和公开的实验数据对比,验证了本文方法的准确性.之后将该模型应用于国内某型燃气轮机涡轮导叶热障涂层的寿命预测.结果表明,随着热生长氧化层的增厚,当达到临界厚度时在陶瓷层和黏结层界面会出现应力反转.陶瓷层和黏结层界面出现的拉伸应力会诱导附近微小裂纹扩展.此时热生长氧化层进一步增厚,将会加速裂纹的扩展速度,直至裂纹贯通,界面出现剥离失效.涂层寿命与服役温度呈指数递减规律,在一定范围内提高陶瓷层和黏结层界面粗糙度可以延长涂层服役寿命.本文模型对预测等离子喷涂的YSZ涂层寿命具有很好的应用价值.
Thermal barrier coatings(TBCs)may gradually degrade from severe thermal environments,eventually leading to spallation and failure during thermal cyclic loading.Atmospheric-plasma-sprayed(APS)TBC was used as the research object in this study.By combining the crack growth model of the subcritical stage,the exponential model of the critical energy release rate,and the improved growth model of the thermally grown oxide(TGO)layer,a life prediction model was derived.The accuracy of the life prediction model proposed in this study was verified by comparing it with the published experimental data.Then,the life prediction model was applied to analyze the performance of TBCs used as thermal protection for the guide vane of a certain type of gas turbine in China.Results showed that with the thickening of the TGO layer,stress inversion occurs at the TBC/BC interface when the critical thickness is reached.The tensile stress at the TBC/TGO interface can induce nearby crack propagation.At this time,further thickening of the TGO will accelerate crack propagation until the crack grows and reaches a critical size and the TBC fails.The time to failure of the TBC decreases exponentially with the serving temperature,and increasing the TBC/TGO interface roughness can effectively extend the service life of the TBC.The model presented in this study has a good application value for the life prediction of the APS TBC.
作者
蒙泽威
刘永葆
殷望添
贾宇豪
贺星
MENG ZeWei;LIU YongBao;YIN WangTian;JIA YuHao;HE Xing(College of Power Engineering,Naval University of Engineering,Wuhan 430033,China)
出处
《中国科学：技术科学》
EI
CSCD
北大核心
2023年第4期631-643,共13页
Scientia Sinica(Technologica)
基金
国家科技重大专项(批准号:J2019-I-0012)资助。
关键词
热障涂层
寿命预测
等离子喷涂
裂纹扩展
thermal barrier coating
life prediction
atmospheric plasma spray
crack propagation
作者简介
刘永葆,E-mail:liuyongbaoly@163.com;贺星,E-mail:xinghe_nue@yeah.net。
