Plastic deformability of metallic glass by artificial macroscopic notches

This paper reports that the plasticity of Zr-based metallic glass can be improved by creating two symmetrical semi-circular notches. Unlike the experimental findings of the samples without notches, a steady shear deformation can be created by the large-scale stress gradient around the two symmetrical notches and the plasticity of metallic glass can be enhanced to a high value of similar to 10% under compression tests. The improved plasticity may be due to the easy initiation of shear bands around the notches, and the consequent blocking effect of notches on the propagation of shear bands, similar to the dislocation mechanism in crystalline materials. To reveal the particular plastic deformation behavior of metallic glass, Ti3SiC2 ceramic and high-strength steel specimens with two symmetrical semi-circular notches were also conducted under compressive loadings; however, no enhancement in plasticity was found. It is suggested that creating a stress gradient is a particular strategy for designing metallic glasses in order to improve their plasticity. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.