Characterization and mechanical modeling of interfacial damage in EB-PVD thermal barrier coatings considering multiple failure factors

In this work, heat treatment experiments at 1050 and 1100 °C were carried out on single-crystal superalloy specimens coated with the electron beam physical vapor deposition (EB-PVD) thermal barrier coating (TBC) system. Furthermore, the evolution of microstructural characteristics and sintering-induced mechanical properties were separately obtained by the field emission scanning electron microscope (FE-SEM) and nanoindenter, providing inputs for damage modeling. Meanwhile, the critical compressive strain of TBCs at room temperature was acquired using 3D digital image correlation (3D-DIC) technology to characterize the interfacial damage combined with the experimentally observed buckling modes. The results demonstrate that not only does oxidative damage exist in the TBCs system due to thermally grown oxide (TGO) growth, but additional damage is generated by thermal cycling and sintering behavior, respectively. Then, a nonlinear cumulative interfacial damage model considering multiple failure factors is developed to predict TBCs’ life. The error between the measured damage and calculated damage is less than 15 %, showing good prediction accuracy.