The dynamic interaction between diffusing H and mobile dislocations in Ni and binary Ni–16wt%Cr was analysed in terms of the solute drag phenomenon. Static strain aging experiments were used to measure the saturated dislocation pinning force as a function of the H concentration. The H-dislocation interactions caused a shielding of the pair interactions between edge dislocations. The influence of this screening effect was analytically evaluated for the line tension of curved dislocations, and an assessment was made of its consequences for the critical force for the expansion of a dislocation loop and for the dissociation mechanism. The results were used to interpret experimental results on the plastic flow of H-charged Ni single crystals, oriented for easy glide. The study illustrated the mechanisms of H-dislocation interactions and their effects upon the various contributions of H to the flow stress of Ni.

Solute-Dislocation Interactions - Modelling and Experiments in Hydrogenated Nickel and Nickel Base Alloys. G.Girardin, D.Delafosse: Materials Science and Engineering A, 2004, 387-389, 51-4