[SY-G5] Investigation on 1/2<11-1>{112} and 1/2<11-1>{123} mixed dislocations in BCC iron by classical molecular dynamics
Mixed dislocation motion of 1/2<11-1>{112} and 1/2<11-1>{123} slip systems in pure BCC iron was observed by using classical molecular dynamics (MD). Angles between Burgers vector and dislocation line, which is referred as mixed dislocation angle, were between 0 degree and 180 degree (i.e., 0 degree and 180 degree correspond to screw dislocation and 90 degree corresponds to edge dislocation). As an initial configuration, one mixed dislocation was introduced in the MD box. Then, shear strain parallel to the slip plane with constant strain rate was applied to glide the dislocation to calculate Peierls stress, or shear stress was applied to calculate mobility and friction stress.The directions of dislocation motion were both twinning and anti-twinning directions. Dislocation mobility and friction stress at 100K and 300K were evaluated as well as Peierls stress. High Peierls stress was observed on a mixed dislocation whose core structure was straight (i.e., it does not contain kinks) since all of the dislocation had to jump to the next position at the same time. On the other hand, low Peierls stress was observed on a mixed dislocation whose core structure contains kinks since it could gradually move through kink movement along with the dislocation line. There seemed that the friction stress and the mobility of the mixed dislocations were affected by the dislocation core structure at 100K; the friction stress was high and the mobility was low at the mixed dislocation angles where Peierls stress was high. On the other hand, there seemed to be less effect of the core structure on the friction stress nor the mobility at 300K. It is found that directions of dislocation motion have almost no effects on the Peierls stress, mobility and friction stress as a whole.