Stress models for electron beam-physical vapor deposition thermal barrier coatings using temperature-process-dependent model parameters

Abstract

This article presents a new stress model for EB-PVD TBC to provide insight into TBC failure mechanisms. Cycling-induced and temperature-process dependent model parameters are incorporated into stress analysis of EB-PVD TBC and then used to simulate the variation of mechanical, thermal and inelastic behaviour from metallic bond coat to thermally grown oxide (TGO). This gives a smooth evolution of residual stresses and is more realistic than prior finite element (FE) work. Two types of interfacial roughness approximate profiles are presented and implemented in the FE model. Geometrical parameters are used to model the interface roughness, and residual stresses are then evaluated at specific positions within TBCs. This article's stress analysis establishes a link between stress distribution and the evolution of interfacial roughness during thermal cycles. Consequently, the results are expected to provide insight into the failure modes related to localized interfacial roughness evolution.