Nucleation and migration of kinks of screw dislocation in BCC iron is simulated using the Langevin dynamics. Static parameters such as Peierls potential and line tension coefficient are derived from first-principles calculations, while dynamic parameters such as effective mass and viscosity coefficient are derived from molecular dynamics simulations. We show that the jerky motion of screw dislocations observed in low-temperature in-situ observation experiments can be possibly attributed to the reflection of kinks at the terminating points of the screw dislocations.
Center for Computational Science & e-System, Japan Atomic Energy Agency