Finite Element Simulation of Residual Stress Development in Thermally Sprayed Coatings

The coating buildup process of Al2O3/TiO2 ceramic powder deposited on stainless-steel substrate by atmospheric plasma spraying has been simulated by creating thermomechanical finite element models that utilize element death and birth techniques in ANSYS commercial software and self-developed codes. The simulation process starts with side-by-side deposition of coarse subparts of the ceramic layer until the entire coating is created. Simultaneously, the heat flow into the material, thermal deformation, and initial quenching stress are computed. The aim is to be able to predict—for the considered spray powder and substrate material—the development of residual stresses and to assess the risk of coating failure. The model allows the prediction of the heat flow, temperature profile, and residual stress development over time and position in the coating and substrate. The proposed models were successfully run and the results compared with actual residual stresses measured by the hole drilling method.