Strengthening and toughening by interface-mediated slip transfer reaction in nanotwinned copper

Molecular dynamics simulation of tensile deformation shows that the high strength of nanotwinned copper is initially the result of the twin boundary pinning effect on dislocation motion, and that interface-mediated slip transfer mechanisms operate in the later stages of deformation. These mechanisms include the complete transmission of screw dislocations across twin boundaries via Fleischer and Friedel-Escaig mechanisms, the incomplete transmission of non-screw dislocations and transinission-induced jog formation. These factors are effective at maintaining the material's high strength and good ductility. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.