Densification and Strain Hardening of a Metallic Glass under Tension at Room Temperature

作者：Z. T. Wang, Jie Pan, Y. Li, Christopher A. Schuh · 发表于：Physical Review Letters · 年份：2013 · DOI：10.1103/physrevlett.111.135504 · 被引用次数：159 · 研究领域：Metallic Glasses and Amorphous Alloys、Material Dynamics and Properties、Theoretical and Computational Physics

The deformation of metallic glasses involves two competing processes: a disordering process involving dilatation, free volume accumulation, and softening, and a relaxation process involving diffusional ordering and densification. For metallic glasses at room temperature and under uniaxial loading, disordering usually dominates, and the glass can fail catastrophically as the softening process runs away in a localized mode. Here we demonstrate conditions where the opposite, unexpected, situation occurs: the densifying process dominates, resulting in stable plastic deformation and work hardening at room temperature. We report densification and hardening during deformation in a Zr-based glass under multiaxial loading, in a notched tensile geometry. The effect is driven by stress-enhanced diffusional relaxation, and is attended by a reduction in exothermic heat and hardening signatures similar to those observed in the classical thermal relaxation of glasses. The result is significant, stable, plastic, extensional flow in metallic glasses, which suggest a possibility of designing tough glasses based on their flow properties.