Numerical modeling of the core structure of [100] dislocations in Fe3C cementite

The core structure of [100] screw dislocation has been modeled in Fe3C cementite, using the Peierls–Nabarro–Galerkin model based on γ-surfaces for (010) and (001) planes. We show that γ-surfaces and core structure of the [100] screw dislocation depend of the relaxation procedure applied to the carbon atoms during γ-surface calculations. We find that [100] screw dislocations spread in (010) with a tendency toward dissociation, which is in agreement with dislocation features observed experimentally.