Dislocation nucleation and propagation in a Cu–Nb bi-layer with an incoherent face-centered cubic/body-centered cubic interface were examined using atomistic simulations. The nano-indentation model was applied to generate dislocations at and near the surface in one of the layers and push them through the interface into the other layer. The reasons for high strength levels in multilayered metallic composites with incoherent interfaces were investigated. The interface acts as a very strong barrier to dislocation propagation. It was found that even under severe deformation at large indentation depths, no dislocations were transmitted across the interface from Cu into Nb. While dislocation transmission from Nb to Cu could be, in general, observed, it occurs under high loading forces. In both cases, the presence of the interface results in considerable strengthening of the bi-layer. Mechanisms of interactions between gliding dislocations and the incoherent interface were studied in detail. In particular, interface shear at the interface under complex three-dimensional loading conditions was analyzed.

Interaction of Dislocations with Incoherent Interfaces in Nanoscale FCC–BCC Metallic Bi-Layers. S.Shao, S.N.Medyanik: Modelling and Simulation in Materials Science and Engineering, 2010, 18[5], 055010