Influence of Thermally Grown Oxide Dynamic Growth Mode and Creep Strength on the Delamination and Failure of Thermal Barrier Coatings in the Furnace Cycle

Growth kinetics and the irreversible deformation of thermally growth oxide (TGO) critically affect the delamination and cracking at the interface of thermal barrier coatings (TBCs). In this study, TGO dynamic growth during furnace cycles is simulated using three different approaches. The stress evolution and damage characteristics near the interface are compared in various TGO growth modes. Furthermore, the influences of TGO creep at high temperatures on the interface delamination and coating failure are also investigated. The results reveal that TGO growth achieved through material transformation (growth mode III) leads to earlier interface delamination compared to element swelling methods (growth mode I and II). Although the stress value in growth mode II is higher than that in growth mode I after all cycles, earlier delamination and spallation occur in mode I due to faster stress accumulation in the initial stage of thermal cycle. Moreover, rapid TGO creep is found to reduce the accumulated stress within the ceramic layer and delay the onset of interface delamination. These findings provide important theoretical insights for the development and life assessment of advanced TBCs.