An atomistic investigation of dislocation velocity in body-centered cubic FeCrAl alloys

Edge, screw, and mixed dislocation velocities in FeCrAl body-centered cubic alloy were investigated by classical molecular dynamics simulation at several temperatures for the < 111 > {110} type slip system. For screw orientation, the dislocation velocity as a function of applied shear stress was found to be zero up to a threshold stress, beyond which the velocity increases with applied shear stress. For edge and mixed orientations, the dislocation velocity as a function of applied shear stress was found to have four regimes: zero value below a threshold stress, slow glide regime just above the threshold stress, a linear regime, and a final nonlinear regime past a certain velocity with a relatively lower slope. Two main features of the dislocation velocity were observed in FeCrAl alloys. First is that the rate of increase of the velocity with the applied shear stress decreases with chromium concentration and aluminum concentration, and that the dependence of the dislocation velocity on the angle between direction of the Burgers vector and the dislocation line direction shows a sinusoidal-like behavior.

Automated summary

The study investigated the edge, screw, and mixed dislocation velocities in FeCrAl body-centered cubic alloy for the <111> {110} type slip system through classical molecular dynamics simulation. Different behaviors were observed for dislocations in screw, edge, and mixed orientations with applied shear stress, including zero velocity below a threshold stress, slow glide regime, linear regime, and nonlinear regime. The study also found that the rate of increase of the dislocation velocity decreases with chromium and aluminum concentrations, and the dependence of the velocity on the angle between the Burgers vector direction and the dislocation line direction follows a sinusoidal-like behavior.