Screw Dislocation Impingement And Slip Transfer At Fcc-Bcc Semicoherent Interfaces

Understanding of dislocation-interface interactions at the atomistic level could provide useful insights into the mechanisms behind slip transfer, a key information for higher length-scale formulations. A sys-tematic study of screw dislocation impingement on both Fe/Al and Fe/Cu interfaces with Kurdjumov-Sachs orientation relationship has been carried out using atomistic simulations. For the "strong" Fe/Al interface, there is appreciable dislocation delocalization, in which the change in dislocation content pro-vided by Nye tensor analysis. Interestingly, the delocalization is significant enough that large simulation cells must be employed in order to avoid boundary effects. When the impinging dislocations are far away from the boundaries, the large accumulation of shear strains nearby the impinging dislocations at the in-terface causes dislocation nucleation/emission at these places. While for the "weak" Fe/Cu interface, the dislocation delocalization at the interface is notably long-range, extending more than 20 nm away from where the initial dislocations entered the interface. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.