Effect of non-uniform growth of TGO layer on cracking behaviors in thermal barrier coatings: A numerical study

The growth of thermally grown oxide (TGO) always induces large deformation and growth stress in thermal barrier coating systems (TBCs), which play a major role in the initiation and propagation of interfacial cracks. In the present work, the influence of TGO non-uniform growth on stress evolution and interfacial crack initiation is investigated by the finite element method. The results demonstrate that, compared with a uniform growth model, the non-uniform growth of TGO increases the magnitude of residual stress in the TC layers and leads to the early initiation of interfacial cracks. Moreover, the difference in maximum stress between uniform and nonuniform growth increases with the increase in interfacial roughness. However, the change in TGO growth mode and interfacial roughness does not change the location of crack initiation, which remains at off-peak locations.