Velocity of mixed dislocations in body centered cubic iron studied by classical molecular dynamics calculations

[Display omitted] •Mixed dislocation velocities in pure iron for [1 1 1] (11-0) slip system were calculated classical molecular dynamics.•Immobile mixed dislocations are found at low temperature.•There are no immobile mixed dislocations at room temperature.•A mixed dislocation was modelled as a combination of two types of segments.•The calculated mixed dislocation velocities are reproduced by the model. The velocity of mixed dislocations in the 11111-0 slip system in body centered cubic iron was investigated with classical molecular dynamics calculations. Local minimum points of the dislocation velocity as a function of the angle between the mixed dislocation line and Burgers vector at low temperatures are found. The local minimum points gradually disappear with the increase in temperature, and the function is smooth at 300 K. Mixed dislocations are modeled with a combination of two types of segments. The segment velocity is modeled based on kink formation and spreading below friction stress, while it is proportional to applied stress beyond friction stress. The dislocation velocity calculated by classical molecular dynamics calculations is reproduced by the model.