Molecular dynamics simulation of screw dislocation behavior under uniaxial compression: Elastoplastic transition of KCl crystal

Molecular dynamics (MD) simulations of screw dislocation behavior in KCl crystal under uniaxial compression along the [100] axis direction were performed to discuss elastoplastic transition under shock compression. The original screw dislocation was dissociated into one screw dislocation and two edge dislocations then generated edge dislocations moved along 45degrees to the compression direction under uniaxial compression. Simulation results showed the minimum stress for dissociation of screw dislocation and generated edge dislocation motion was from 3.1 to 3.3GPa. Its stress is larger than the stress in case of uniaxial compression for edge dislocation. The large stress may be caused by the difficulty in moving ions due to a helical configuration around screw dislocation core and dissociation of screw dislocations.