RelAtions between miCrostructure meChanics and OxidatiON – RACCOON

Life time prediction of a metallic alloy subjected to high temperature oxidation is a challenge of major industrial interest. The multi-physical and multi-scale natures of the interactions at play during high temperature oxidation require considering the strong couplings between chemical and diffusional processes, microstructure, mechanical effects and thermal effects.
The RACCOON project aims at describing, characterizing and modeling these couplings at different scales in model alloys with simplified metallurgy. The project follows an upstream approach with the ambition to provide fundamental knowledge on the relationships between high temperature oxidation of metallic alloys and the evolution of inelastic deformations. It aims at linking the meso- and macro- scales through connections between phenomena at micro and mesoscopic scales and phenomenological models that can be used at larger scales.
The main objectives are to characterize the fundamental mechanisms at the origin of the impact of the mechanical state of the material on the oxidation rates and the interdependence between the mechanical stresses evolution and the oxidation rates. The purpose is to clarify the origin of the relationships between high temperature oxidation and mechanical behaviour. The experimental results will be capitalized through a phase-field model which development is an objective of the project. The phase field approach enables to simulate the microstructural evolution of heterogeneous materials. Its application to high temperature oxidation is tricky because of the complexity of the encountered systems. A phase-field model including the diffusion mechanisms linked to oxidation, large deformations and creep will allow an unprecedented numerical description allowing a better interpretation of the experimental results.