热障涂层氧化和热疲劳寿命实验研究

An Experimental Study of Oxidation and Thermal Fatigue of TBC

本论文是热障涂层氧化和热疲劳寿命研究工作的第一部分,主要针对等离子、EB-PVD两种类型的涂层,开展涂层的氧化和热疲劳实验研究,并为后面建立和校核涂层的寿命预测模型奠定实验基础。整个研究工作的重点放在设计合适的实验方案或方法,了解国内目前涂层喷涂工艺水平下涂层的寿命特点和失效模式,并结合微观的分析,了解涂层氧化和热疲劳失效的机理。整个实验工作分为涂层氧化实验和热疲劳实验;氧化实验考虑到了氧化增重和氧化层厚度的两个参量的测量;热疲劳考虑到了主要由循环热不匹配应力引起的寿命失效和带高温保持时间的热循环疲劳失效,及其氧化的影响。

The research results presented here are first part of the oxidation and thermal fatigue research of TBC (Thermal Barrier Coatings),which was mainly concerned with the experiments of oxidation and thermal fatigue for two types of TBC:plasma sprayed and electrical beam physical vapor deposition coatings,and prepared for further modeling of fatigue life prediction of TBC.At first,whole research work focuses on designing a set of suitable experiment methods for evaluating the failure characteristics and modes of oxidation and thermal fatigue of TBC at current domestic spray technique level.The failure mechanisms of oxidation and thermal fatigue of TBC are investigated with the aid of SEM.The project includes the TBC oxidation experiment and TBC thermal cyclic experiments.Both gain of oxidized weight and thickness of oxidized layer were measured during oxidation experiments,and used for modeling evolution of oxidation.Thermal cyclic fatigue experiments included the fatigue mainly induced by thermal cyclic mismatched stress and thermal cyclic fatigue with hold time at peak temperature.All experiments included the effect of preoxidation.