Inter-zone constraint modifies the stress-strain response of the constituent layer in gradient structure

How an individual constituent zone behaves during the deformation of a heterostructured metallic material is fundamental issue for understanding heterostructure deformation, but it remains challenge to experimentally observe it. Here we report study on stress-strain behavior nanostructured gradient layer (NGL) in integrated specimen that consists coarse-grained (CG) central sandwiched between two NGLs. Constraint from CG led formation dense and dispersed stable strain bands (SBs) NGL, which regained dislocation hardening after initial recovery grain coarsening. Consequently, NGL exhibited transient plateau flow stress yielding, then extra achieve excellent uniform elongation. These unique behaviors are dramatically different those freestanding indicating fundamentally principle intrinsic heterostructures, i.e., inter-zone constraint modifies constitutive zones.