Stress evolution of TBCs considering the micro morphology characteristics with multi-oxides growth

Abstract

Thermal Barrier Coatings (TBCs) are a fundamental technology for safeguarding aircraft engine blades from high-temperature environments. Under long-term exposure to a high-temperature environment, breakaway oxidation of multi-metallic metals occurs in TBCs. The growth of multi-metal oxides and stress evolution in the TBCs after breakaway oxidation is very complex for a real coating microscopic morphology. In this paper, we use the CT image technology to construct the TBCs model of the reflective TBCs microscopic morphology and use a user-defined element (UEL) subroutine involving the growth of the multi-oxides model to calculate the stress. We focus on the evolution of interfacial stress in the first and second oxide stages. The results show that the micro defects will cause multiple increases in the maximum stress near the defects in TBCs. Meanwhile, microscopic defects near the interface can bring a sharp increase of tensile stress in the local area during the cooling stage, which can easily cause cracking and delamination of the interface.