A Jogged Dislocation Governed Strengthening Mechanism in Nanotwinned Metals

Abstract

Atomistic simulations reveal a new and unique strengthening mechanism in nanotwinned metals governed by the collective motion of multiple necklace-like extended jogged dislocations. This mechanism prevails in a columnar-grained nanotwinned metal subject to an external stress parallel to the twin planes, provided the twin boundary spacing falls below a critical value. A theoretical model based on the depinning of unit jogs on twin planes is proposed to determine the flow stress associated with this deformation mechanism and is shown to be in agreement with atomistic simulations.