Effect of the dynamic loading rate on the failure of bulk metallic glasses

Abstract
The absence of structural ordering in bulk metallic glasses (BMGs) leads to plastic deformation controlled by shear bands initiation, propagation, and interactions which differ most likely when quasi-static or dynamic loads are applied. Under quasi-static loading and high hydrostatic stress, the shear band initiation and propagation process is stable which can result in large plastic deformation in excess of 0.50. Under dynamic loading conditions, BMGs are brittle. The objective of the present study was to examine the influence of the dynamic loading rate on the failure mechanisms of a Zr₅₇Ti₅Cu₂₀Ni₈Al₁₀ BMG. Dynamic compression tests were conducted with a direct impact compression apparatus over a wide range of dynamic strain rates from 570 to 7760 s⁻¹. The decrease of the dynamic failure stress with the increase of strain rate was interpreted through the analysis of observed failure mechanisms.