Numerical simulations of hydrogen–dislocation interactions in fcc stainless steels. : part I: hydrogen–dislocation interactions in bulk crystals

Abstract

The basic equations for the coupling between stress and hydrogen diffusion are presented. A numerical simulation method is proposed. It is based on the diffusion equation including a hydrostatic stress gradient term, and on a discretisation of the hydrogen concentration field. The simulation scheme is applied to elementary dislocation configurations in order to compute the influence of solute hydrogen on dislocation interactions. A simple general expression is derived for the hydrogen screening effect on the pair interactions between co-planar dislocations. This expression is used to investigate the influence of diffusing hydrogen on the cross-slip probability of screw dislocations. First numerical results are presented. They are discussed in relation with the modelling of transgranular stress corrosion crack propagation.