An atomistic study was conducted on the effect of H, which was homogeneously distributed in a stacking fault, on the activation energy of the cross slip of a screw dislocation in Ni using the embedded-atom method. The global minimum energy configurations with H in the stacking fault and the cross-slip processes were determined by the nudged elastic band method. It was revealed that H in the stacking fault increased the activation energy of cross slip significantly, due to the increase in the separation between partial dislocations induced by H. The increase in the activation energy induced by H in the stacking fault was much larger than that induced by H bound to dislocation cores during cross slip. The present study provided direct evidence that H in the stacking fault was the controlling mechanism for H-inhibited cross slip, and thus, H-induced slip planarity in common face-centred cubic materials where dislocations dissociate into partial dislocations.

Cross-Slip Process in FCC Nickel with Hydrogen in a Stacking Fault - an Atomistic Study using the Embedded-Atom Method. M.Wen, S.Fukuyama, K.Yokogawa: Physical Review B, 2007, 75[14], 144110 (5pp)