The tensile fracture behavior of the sandwich-structured Ni/Cu/Ni composites was investigated. The results reveal that an evident transition of the fracture behavior from the necking-delayed ductile mode with sufficient co-deformation of both-side Ni layers to the necking-inhibited brittle mode accompanied by interface delamination with decreasing the thickness ratio of the middle Cu layer to the Ni layer. A model based on beam deflection was proposed to elucidate the role of the Ni layers in delaying necking of the Cu layer. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
