Dynamic simulation of edge dislocation dipole in bcc-Fe

Molecular dynamics simulations (MD) are used to investigate dynamic process of an edge-dislocation dipole in gliding face (011) with Burgers vector b=±[100] in bcc single-crystal iron. Simulation results reveal that: for the positive edge dislocation gliding along direction, the core atoms above the gliding face pass through Peierls potential barrier by slipping along [111] direction and those below the gliding face by slipping along [1̄11] direction; and then slipping directions of core atoms turn to [11̄1̄] and [1̄1̄1̄] correspondingly, while the core energy is released by phonon. Velocity and Peierls potential barrier of dislocations, as functions of time and distance between dislocations, are calculated. Results show that for the case of long distance, Peierls potential barrier remains invariable and dislocations glide at a speed of 1.05 km/s; for the case of short distance (<5 b), Peierls potential barrier reduces rapidly and dislocations begin to accelerate, and before annihilating the velocity of dislocations arrives at 2.31 km/s.