Modeling residual stresses generated in Ti coatings thermally sprayed on Al2O3 substrates

Abstract

There is described a method of modeling by the finite element method the residual stresses induced during thermal deposition of coatings. The simulation was performed in two stages. The first dynamic stage simulated the impacts of the individual particles of the coating material onto the substrate, and the next static stage included a non-linear thermo-mechanical analysis intended for simulating the process of layer-by-layer deposition of the coating, with a specified thickness, and then cooling the entire system to the ambient temperature. In the computations, the samples were assumed to be cylindrical in shape and composed of an Al2O3substrate and a titanium coating (with three different thicknesses) deposited using the detonation method. The correctness of the numerical model was verified experimentally by measuring the deflections of a real Ti coating/Al2O3 substrate sample with the Ti coating detonation-sprayed on the ceramic substrate, after cooling it to the ambient temperature. The experimental results appeared to be in good agreement with those obtained by the numerical computations.