Activation analysis of dislocation nucleation from crack tip in α-Fe

Guided by a recent molecular dynamics simulation study of mode I crack-tip environment in α-Fe using an embedded atom method potential, an activation analysis of the nucleation of a half-square dislocation loop from the tip of a tensile crack has been carried out based on the Rice and Thomson approach [Philos. Mag. 29, 78 (1974)]. The effects of elastic softening due to stress and temperature as well as the nonlinear stress distribution around the crack are introduced by incorporating the simulation results self-consistently into the analysis, reducing the previously overestimated activation barrier by a factor of over 15.