Atomistic simulations were conducted on the H-affected kinking process of a screw dislocation in Fe by the nudged elastic band method. It was found that when a kink pair nucleated at H, the activation energy was decreased by the transition of H to a stronger binding site, while it was increased by the transition to a weaker binding site. When a kink pair met H during expansion, sideward motion of the kink pair was impeded by H. The simulation provided insights into the complex atomistic process of H-induced softening and hardening.

Atomistic Simulations of Effect of Hydrogen on Kink-Pair Energetics of Screw Dislocations in BCC Iron. M.Wen, S.Fukuyama, K.Yokogawa: Acta Materialia, 2003, 51[6], 1767-73