Cellular automata modelling of intergranular corrosion

Cellular Automata (CA) modelling is a lattice representation into identical cells related between one another and with their neighbourhood by a set of rules which determine the system's evolution. Within this approach it is possible to model various phenomena in different domains of which physics, biology or chemistry. Important advances concerning the modelling of corrosion within the CA framework have been accomplished recently at the CEA. Existing 2D models have successfully been generalized to more realistic 3D representations, as well as the modelling of the coupling between anodic and cathodic reactions. This has made it possible within a single framework to model generalized and localized corrosion (pitting, occluded corrosion). The PhD proposed falls in the continuation of a previous thesis and should shed new light in the modelling of phenomena appearing in intergranular corrosion (IGC). The CA approach is indeed well adapted to describe process involving moving boundaries (which is indeed the case in IGC) and to model systems where there exist parameters describing stochastic process - singularity of composition at grain boundaries, presence of clusters, local segregations of impurities inducing local variations of reactivity. We shall study in particular the effect of the concentrations of the electrolytes and of the oxidising ions. A main objective of the PhD is to introduce the notions of kinetics of the anodic and cathodic electrochemical reactions in the IGC model that shall be developed. This model will take into account diffusion of species in the electrolyte (we will try to improve the CPU-GPU specific algorithm implemented in parallel computation in the CUDA environment), we shall verify advances in the modelling by testing quantitative predictions for IGC obtained within the CA approach. (author)