Numerical study on interfacial damage of sprayed coatings due to thermo-mechanical fatigue

Abstract

In order to protect materials, thermally sprayed metallic coatings are applied to the surface of structural components operating at high temperatures and in corrosive media. The mesostructure of these coatings mainly consist of deformed flattened particles partially separated by small oxide interface layers. In this study, the FEM implementation of a representative volume element of a coating is presented focussing on the odelling of interfaces. The structure is approximated as a hardcore Voronoi mosaic, based on randomised seeds. While the particles are meshed with standard volume elements, cohe- sive elements are used for the interfaces. A cyclic traction-separation law is implemented to account for damage initiation and evolution under cyclic loading until failure. Com- pared with experimental observations, the results of the FEM computation demonstrate the applicability of the model to predict static and cyclic damage evolution as well as delamination.