Atomistic Simulation of Cracktip Failure Pathways in α-Fe

In this work, we present atomistic simulations with EAM potentials to identify the activated pathways and energetics for dislocation loop emission from an atomically sharp cracktip in single crsytal α-Fe. Nudged elastic band calculations are used to identify saddlepoint transition states and energy barriers for dislocation emission at sub-critical stress intensities. From these calculations, the likely influence of these pathways on the ductile to brittle transition temperature is inferred.