Interfaces with relatively low shear strengths could be strong barriers to glide dislocations due to dislocation core spreading within the interface plane. Using atomistic modelling the influence of interface shear strength on the interaction of lattice glide dislocations with fcc/bcc interfaces was studied. So-called tunable interatomic potentials were used to vary the interface shear strength for the same interface crystallography. The resulted showed that: (1) the interface shear strength increased as the dilute heat of mixing decreased; (2) the interface shear mechanism involved the nucleation and glide of interfacial dislocations, which was dominated by the atomic structures of interfaces, regardless of the interface shear strength; (3) weak interfaces entrap lattice glide dislocations due to the interface shear and core spreading of dislocations within interfaces. Reverse shear displacement was needed to enable collapse of the spread core for slip transmission. This study provided an insight into the correlation between interface shear strength and glide dislocation trapping at the interface, which was a crucial unit mechanism in understanding the ultra-high strengths observed in nanoscale fcc/bcc multilayers.

The Influence of Interface Shear Strength on the Glide Dislocation–Interface Interactions. J.Wang, R.G.Hoagland, X.Y.Liu, A.Misra: Acta Materialia, 2011, 59[8], 3164-73