Investigation of structure and energy of edge dislocation in bcc iron

Based on the theory of dislocations, we have constructed the four models of the < 100 > {010}, < 100 > {011}, 1/2 < 111 > {001} and 1/2 < 111 > {112} edge dislocations in bcc Fe using the molecular dynamics method, and the formation energy, core energy and core radius of the dislocations have been calculated respectively. The calculated results indicated that the formation energies of < 100 > {010} and < 100 > {011} edge dislocations are higher than those of 1/2 < 111 > {011} and 1/2 < 111 > {112} edge dislocations. This shows that the formation of 1/2 < 111 > edge dislocation is easier than that of (100) edge dislocation. However, the core radii of < 100 > {010} and < 100 > {011} edge dislocations are smaller than those of 1/2 < 111 > {011} and 1/2 < 111 > {112} edge dislocations. This shows that the atomic numbers locating at the singular region in the 1/2 < 111 > edge dislocation are greater than those in < 100 > edge dislocation. Therefore, the motion of 1/2 < 111 > edge dislocation is easier than that of < 100 > edge dislocation.