热障涂层循环热生长稳定性  

Stability of Thermal Barrier Coatings(TBCs)under Cyclic Thermal Growth

作　　者：徐颖强[1] 孙戬[1] 李万钟[1] 陈亚亚[1] 吕凯[1] 许璠 

机构地区：[1]西北工业大学机电学院,陕西西安710072

出　　处：《西北工业大学学报》2015年第6期949-955,共7页Journal of Northwestern Polytechnical University

基　　金：国家自然科学基金(11072196;5875214;10672134);陕西省自然科学基金(2015JM1009)资助

摘　　要：循环热载荷下热障涂层(TBCs)界面氧化生长的本质是陶瓷层(TC)/黏接层(BC)界面间相转变引起的界面结构和材料组织演化,同时,由于各层材料的热不匹配等因素,直接影响着涂层界面的应力场和稳定性,而该应力场和稳定性的演化是研究航空热障涂层层裂和剥落失效的关键因素。考虑氧化层增厚对应力应变场的影响,利用材料转换的方法实现氧化生长,并运用氧化扩散及弹塑性蠕变和安定理论,建立了TBCs循环热生长结构稳定性评价方法,基于试验所得氧化层生长规律,通过半圆形涂层界面模型循环氧化分析,探究了循环热生长对热障涂层应力及稳定性的影响。结果表明,从应力应变演化规律判断,TBCs局部稳定性随氧化生长而减弱,从结构应变能进行评价,随着循环氧化的进行,TBCs表现出不稳定性。The oxide growth of TBCs under cyclic thermal loading is mainly because of the evolution of interfacial structure and material texture caused by phase transition between ceramic top coat （TC） and bond coat （BC）. Be- cause the thermal expansion does not match layers of materials, the interfacial stress field and stability become more complicated, but the changes in stress field and stability are key factors that affect the spalling failure of TBCs. The thickening of thermal growth oxidation which is the main cause for TC spalling is studied and simulated with the ma- terial property change method. Taking into consideration the thermal cycling, the method of structural stability eval- uation based on strain energy is worked out, using the diffusing oxidation and elastic-plastic creep and shakedown theory. The effect of TGO thickening on the stability and stress of TBCs is analyzed through simulating TBCs with the semicircle based on the TGO growth law obtained with experiments. It is concluded that with the estimation of the stress-strain evolution behavior, the local stability of TBCs decreases with the TGO thickening and that TBCs are unstable with TGO thickening as shown by energy.

关 键 词：蠕变 熵 能量耗散 评估 有限元法 数学模型 残余应力 稳定性 应变能 热障涂层 张量 氧化生长 

分 类 号：TG174.4[金属学及工艺—金属表面处理] O341[金属学及工艺—金属学]