Microfracture by pile-up formation at a stress corrosion crack tip : Numerical simulations of hydrogen/dislocation interactions

Abstract
This paper presents a simulation method that is aimed at investigating the elementary mechanisms governing the process of Stress Corrosion Cracking under cathodic hydrogen discharge. Key issues concerning the experimental evidences of localised corrosion - deformation interactions and the relevant modelling are briefly recalled. The simulation method is introduced and the first results on elementary configurations outline the basic mechanisms of hydrogen - plasticity interactions at a Stress Corrosion crack tip. The effect of hydrogen on the density of a dislocation pile-up is examined. The particular situation at the tip of a loaded crack is examined via the introduction of image forces on diffusing interstitial hydrogen. Conclusions are drawn concerning the basic ingredients of the model, as well as future developments of the simulation technique.