Abstract Scope |
Nanolayered, bimetallic composites are receiving increased attention due to an exceptional combination of strength and thermal stability not possible from their coarse-layered counterparts or constituents alone. Yet, due to their 2D planar, unidirectional arrangement, they are highly anisotropic, which results in limited strain hardening and ductility. Here we present the formation of a novel hierarchical microstructure, comprised of crystals consisting of 3D nanolayered alpha/beta-Zr networks. By direct comparison with coarse-layered material of the same chemistry, we show that the unusual hierarchical 3D structure gives rise to high strain hardening, high strength and high ductility. We discovered that the 3D randomly oriented bi-phase boundaries result in progressively dispersive rather than localized slip with increasing strain. Dislocation activity in the alpha-Zr lamellae transitions from single slip to multi-slip and eventually to multi-modal slip as strain increases. Ref. PRL-2019-255501 and MRL-2020-8-307. |