Effects of interface roughness on residual stresses in thermal barrier coatings

Using a newly developed object-oriented finite-element analysis method, both an actual microstructure and model microstructures of a plasma-sprayed thermal barrier coating system were numerically simulated to analyze the fullfield residual stresses of this coating system, Residual stresses in the actual microstructure were influenced by both the irregular top-coat/bond-coat interface and cracks in the top coat. By treating the microcracked top coat as a more-compliant solid microstructure, the effects of the irregular interface on residual stresses were examined. These results then could be compared to results that have been obtained by analyzing a model microstructure with a sinusoidal interface, which has been considered by some earlier investigators.