Tension-compression asymmetry of shear band stability in bulk metallic glasses

Abstract

Shear band stability is measured for a Zr-based bulk metallic glass in compressive bending and compared with previous results in tension. Compressive failure is induced via bending of trapezoidal cross-section beams. This characterization is done at multiple fictive temperatures and compared with results in tension, revealing a compression-tension asymmetry in shear banding stability. Stability, indicated here as the ability to resist catastrophic shear bands in favor of stable, arrested shear bands, is higher in compression than tension at all measured fictive temperatures. This asymmetry suggests that shear band propagation is different in tension and compression, and possible mechanisms underlying this difference are suggested. Additionally, this stability measurement is shown to be consistent in uniaxial compression testing, demonstrating its potential for predicting a brittle vs. ductile response in different loading modes of bulk metallic glasses.