Stick-slip behavior of serrated flow during inhomogeneous deformation of bulk metallic glasses

Accurate compression tests with a piezoelectric load cell and an acquisition rate of up to 10 kHz were performed on a Zr-based bulk metallic glass in the temperature range 210-320 K at a strain rate of 10^-3 s^-1. Information about the stress drop magnitude and the associated size of shear displacements as a function of temperature and strain provides detailed insights into the shear band characteristics, which can be described by a stick-slip process. The average shear slip displacement is on average about 1-2 μm, irrespective of temperature, whereas the associated slip time (or stress drop time) increases from ∼1 ms at 320 K to ∼0.4 s at 213 K, yielding values on the deformation kinetics and the shear viscosity. Scanning electron microscopy investigations on shear surfaces and in situ acoustic emission measurements provide further understanding into the complex multistep shear slip process.