Small-volume aluminum alloys with native oxide shell deliver unprecedented strength and toughness

TitleSmall-volume aluminum alloys with native oxide shell deliver unprecedented strength and toughness
Publication TypeJournal Article
Year of Publication2017
AuthorsLi, S-H, Han, W-Z, Li, J, Ma, E, Shan, Z-W
JournalActa Materialia
Volume126
Pagination202 - 209
Date Published2017/03//
ISBN Number1359-6454
Keywordsal-alloys, Aluminum, copper, deformation-behavior, ductility, in-situ, micropillars, nanopillars, Native oxide shell, shear-resistant, Small-volume metals, strength, tensile, Toughness, ultrahigh strength
Abstract

Mechanically robust nanoscale metallic materials are highly desirable in many miniaturized devices. However, the lack of strain hardening and controllable plasticity plagues such small-volume metals. Using Al-4Cu alloy as an example, here we show that a submicron-sized metallic material with ultrathin native oxide shell exhibits a high degree of deformation controllability, unprecedented strain hardening, size strengthening and toughness, in uniaxial tensile deformation. The metal native oxide "composite" is easy to make, and the emergent properties extend well beyond the benchmark range known for metals in a normalized (i.e., dimensionless) strength-toughness plot. The origin of the combination of strengthening and plastic stability is that an intact ultrathin native oxide shell exerts a strong confinement on dislocation movement and annihilation, thereby breaking the envelope on dislocation storage and strain hardening achievable in small-volume metals. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Short TitleActa Mater.