A dislocation dynamics analysis was used to investigate the strength of nanoscale metallic multilayered composites. Several possible interactions between threading (glide) dislocations and intersecting interfacial dislocations were considered and found to lead to strength predictions in better agreement with experimental trends and significantly higher than the predictions of the simplified confined layer plasticity model based upon Orowan bowing of single dislocation in a rigid channel. The strongest interaction occurred when threading and intersecting interfacial dislocations had collinear Burgers’ vector and involved an annihilation reaction at their crossing points followed by the resumption of threading with a new dislocation configuration. The other possible dislocation intersections involve the formation of junctions, which were found to be more complex than simple models suggest. When the layer interfaces were modelled as impenetrable walls, as in existing analytical and some dislocation dynamics models, the predicted strengthening effect was weaker than that predicted by dislocation dynamics with more physical boundary conditions at the interfaces.

Dislocation Dynamics Analysis of Dislocation Intersections in Nanoscale Metallic Multilayered Composites. F.Akasheh, H.M.Zbib, J.P.Hirth, R.G.Hoagland, A.Misra: Journal of Applied Physics, 2007, 101[8], 084314