Oxidation-induced stresses in ceramic-metal interfaces

The oxidation-induced stresses, which are known to control the interface degradation and eventual failure of ceramic-metal interfaces at high temperatures, are calculated using a constitutive framework coupled with the diffusion of oxidant species through a multi-phase solid. The proposed constitutive model accounts for the phase transformation associated with the oxidising phase, and incorporates the effect that the local volumetric expansion of the newly formed oxide has in the generation of inelastic volumetric strains and stresses. The formulation is implemented into the finite element method and used to investigate the evolution of the interfacial stresses induced by the gradual oxidation of a typical thermal barrier coating system.