Cross-slip process in fcc nickel with hydrogen in a stacking fault: An atomistic study using the embedded-atom method

Abstract

An atomistic study is conducted on the effect of H, which is 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 are determined by the nudged elastic band method. It is revealed that H in the stacking fault increases 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 is much larger than that induced by H bound to dislocation cores during cross slip. The present study provides direct evidence that H in the stacking fault is the controlling mechanism for H-inhibited cross slip, and thus, H-induced slip planarity in common fcc materials where dislocations dissociate into partial dislocations.