6.A coupled thermo-chemicalmechanical model forinterfacial oxidation in thermal barrier coatings with large deformation

Abstract:

A nonlinear oxidation kinetics model for TGO was developed based on thermo chemomechanical coupling mechanisms.Through finite element simulations,the coupled thermochemomechanical interactions during TGO nonlinear growth at TBC interfaceswere systematically investigated. Results demonstrate that compared to the conventional Wagner oxidation model,the proposed modelmore accurately describes the heter ogeneous growth characteristics of TGO. The coupling effects significantly inhibit oxygen diffusion,reducing TGO thickness by 14. 60% at crest regions of the TGO interface and 13. 10% at valley regions of the TGO interface,consequently lowering interfacial stress levels. The model reveals the nonlinear growth behavior of TGO and the stress evolution mechanismsunder multifield coupling effects.

Keywords: thermal barrier coating;thermally grown oxide;interfacial stresses;thermochemomechanical coupling