基于随机介质理论的热障涂层随机孔隙模型构建

基于随机介质理论、采取统计学方法,将热障涂层(TBCs)中孔隙和裂纹引起的局部密度和弹性模量起伏用空间自相关函数及某些统计参数来描述,借助极值搜索法对连续随机介质模型进行改造,并针对涂层孔隙率及各向异性取向等进行模型参数优化,提出并建立了TBCs随机孔隙模型。将模型模拟结果与ZrO2涂层SEM观察结果进行对比表明,所建立的模型能够较好地描述热障涂层中的孔隙、裂纹形貌特征。本研究对于确定TBCs孔隙特征与涂层性能的理论关系以及涂层性能计算研究具有较大意义。

Establishing TBC Random Pore Model Based on Random Media Theory

The local variety of density and elastic modulus in thermal barrier coatings (TBCs) caused by pores and cracks is described by the spatial autocorrelation function and statistical parameters in this paper firstly, based on the random media theory and statistical analysis method. A novel TBCs random pore model (TRPM) is proposed and established through rebuilding the continuous random media model (RMM) by extremum search method and parameter optimization for the characteristics of coating porosity and anisotropy orientation. The comparison is carried out between the image of TRPM and scanning electron microscope (SEM) of ZrO2 coating with porosity 1%, which shows TRMM can better describe the morphology characteristics of pores and cracks in TBCs. This work is of great significance for determining the theoretical relation of TBCs pore character and coating performance, and investigation on the calculation of coating performance.