Anomalous reactions of a supersonic coplanar dislocation dipole: Bypass or twinning?

Using atomic-scale simulation, we show for the first time that when two oppositely signed, coplanar dislocations glide towards one another at transonic and supersonic speeds, they do not annihilate. Depending on the shear direction, they either overshoot one another or nucleate twins. These anomalous responses are explained by inertial and relativistic effects on the dislocation core at high velocities. Their discovery deepens the understanding of materials behavior under extreme rates of deformation. Published by Elsevier Ltd. on behalf of Acta Materialia Inc.