Simulation of residual stress and elastic energy density in thermal barrier coatings using fast Fourier transforms

A numerical method for solving the thermoelastic problem in heterogeneous polycrystals based on fast Fourier transforms is applied to thermal barrier coating systems. Several high resolution microstructures are generated synthetically to approximate thermal barrier coatings, with control over the grain size, grain morphology, and texture. Interfaces between coating layer materials are further modified by applying a localized Potts model to introduce interface rumpling. The global results of residual stress and elastic energy density are compared across the various microstructure instantiations. The local variations in elastic energy density are correlated to the amount of interface rumpling. The simulation result are also compared to an analytical result for an idealized interface morphology. The implications of the behavior of the local variations in elastic energy density are discussed in the context of thermal barrier coating failure. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.