The mechanism of power-law scaling behavior by controlling shear bands in bulk metallic glass

Abstract

Bulk metallic glasses deform irreversibly under a stress through shear-banding courses that manifest as the serrated flow behavior. The compressive deformation and dynamic serrated flow behavior of Zr52.5Cu17.9Ni14.6Al10Ti5 bulk metallic glass samples with different aspect ratios have been investigated. The yield strength nearly remains a constant value of approximately 2GPa, while the compressive plasticity increases obviously with decreasing aspect ratio. It is found that the serrated flows display a power-law scaling behavior at different aspect ratios. The power-law scaling behavior is discussed by controlling shear bands in BMG. In addition, a new method was proposed to study the power-law-scaling behavior. When the aspect ratio is small, the friction between the sample and the platen will play a significant role that attributes to a lateral constraint. The uniaxial stress and the lateral constraint will cause a hydrostatic pressure on the sample close to the platen. The shear bands are controlled by the different stress states, which leads to a power-law-scaling behavior in serrated flows. The investigations have a contribution to understanding the plastic-deformation mechanism of BMGs.