Dislocation mechanisms and symmetric slip in rolled nano-scale metallic multilayers

Self-supported Cu-Nb multilayered foils, synthesized by sputter deposition, show significantly different deformation behavior during rolling when the as-deposited individual layer thickness is in the few tens of nanometers range as compared to the micrometer-scale. While the rolled micrometer-scale multilayers exhibit dislocation cell structure formation and large lattice rotations of the interface plane normal, the nano-scale multilayers reveal no dislocation cell structures and insignificant rotations of the interface normal. The observed behavior following large plastic strains is interpreted in terms of dislocation mechanisms of deformation in nano-scale laminates that result in symmetric slip. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.