Relaxed energy and structure of edge dislocation in iron

With modified analytical embedded-atom method and molecular dynamics simulation, this paper simulates the strain energy and the equilibrium core structure of a\langle 100 \rangle edge dislocation in BCC metal iron on atomistic scale. In addition, the trapping effect of dislocation on vacancy is investigated as well. The results show that the equilibrium dislocation core is quite narrow and has a C_2v symmetry structure. Calculated strain energy E_s of the dislocation is a linear function of \ln (R/2b) while R\ge 5.16~\AA (1 Å=0.1 nm), in excellent agreement with the elasticity theory prediction. Determined core radius and energy are 5.16~\AA and 0.62~eV/\AA, respectively. The closer the vacancy to the dislocation line is, the lower the vacancy formation energy is, this fact implies that the dislocation has a trend to trap the vacancy, especially for a separation distance of the vacancy from dislocation line being less than two lattice constants.