A mechanism-based methodologies to model microstructural evolution and predict lifetime of oxidation resistance coatings and TBCs using phase-field simulation is presented wherein only fundamental properties of materials such as free energy, atomic mobility and elastic constants are employed. Phase field approach to simulate critical phenomena associated with TBC failure, namely sintering of ytrria-stabilized zirconia (YSZ) topcoat, (t’→f+m) phase transformations in YSZ topcoat, high temperature oxidation (i.e., growth of thermally grown oxide, TGO) of bond coats, multicomponent-multiphase interdiffusion between bond coats and superalloy substrate, and fracture at the YSZ/TGO and TGO/bond coat interfaces are presented based on available literature. Results from simulation of microstructure evolution due to multiphase-multicomponent interdiffusion between bond coat and superalloy substrates are highlighted with an emphasis on composition-dependent interdiffusion. Specifically, a phase field model has been utilized to simulate and predict interdiffusion behavior and evolution of microstructure in multi-phase diffusion couples of binary and ternary systems, e.g. Ni-Al and Ni-Cr-Al. The model was capable of predicting composition profiles, diffusion paths and dissolution kinetics of the second phase, which were in good agreement with the experimental results reported in the literature.

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