Spatiotemporally inhomogeneous plastic flow of a bulk-metallic glass

With geometrically-constrained specimens, the spatiotemporally inhomogeneous deformation of a Zr-based bulk-metallic glass in uniaxial, quasistatic, compression was investigated. Decreasing the height/width ratio of specimens from 2 to 0.5 significantly increases the plastic strain from 2% to about 80%. Using an infrared camera, we first observe in situ dynamic shear-banding operations during compression at various strain rates. The shear banding is highly dependent on strain rates, either intermittent at the lower strain rate or successive at the higher strain rate. Scanning electron microscopy observations show the spatiality of the rate-dependent shear banding. The serrated plastic flow is a result of the shear-banding operations. At the lower strain rate, more simultaneous shear-banding operations result in more obvious serrations, while at the higher strain rate, fewer simultaneous shear-banding operations cause less obvious serrations.