Huge reduction of Young's modulus near a shear band in metallic glass

A Zr-based bulk metallic glassy sample was subjected to the mechanical compression test at room temperature. The elastic modulus variation in the surface regions near and far from a shear band with a shear step of about 2 gm was measured using the atomic force microscope (AEM) quantitative nano mechanical mapping method. It was found that Young's modulus decreases gradually towards the shear bands mid-plane on the micrometer scale. Maximum decrease in the Young's modulus near the shear band's central region is about 70% on nanometer scale. Such a huge increase in elasticity close to the central plane of the shear band is attributed to the generation and migration of the excess volume during the shear band operation and possible formation of nanovoids. (C) 2016 Elsevier B.V. All rights reserved.