Thermally activated process of homogeneous dislocation nucleation and hydrogen effects: An atomistic study

Molecular dynamics simulations are conducted on the H-affected homogeneous dislocation nucleation of an initially virgin face-centered cubic lattice Ni. By theoretical analysis of the statistical distribution of the critical strains for homogeneous dislocation nucleation on the basis of transition state theory, we extract the activation energy and volume as a function of strain and temperature. We demonstrate that the critical dislocation embryo is small and H decreases the activation energy and volume, which leads to enhanced homogeneous dislocation nucleation.