Cryogenic charpy impact toughness of (Ti41Zr25Be26Ni8)93Cu7 bulk metallic glass

Abstract

The Charpy impact toughness of standard-size (10 × 10 × 55 mm) (Ti41Zr25Be26Ni8)93Cu7 and (Ti41Zr25Be28Fe6)91Cu9 bulk metallic glasses (BMGs) samples from room temperature to cryogenic temperature are systematically studied. Although a ductile-to-brittle transition behavior is observed, the (Ti41Zr25Be26Ni8)93Cu7 BMG still keeps a relatively robust impact toughness of 48 kJ/m2 at 81 K, which is 66% of that at 298 K. With decreasing temperature, the fracture morphology changes progressively from vein patterns to periodic nanoscale wavy corrugations, indicating a transition in deformation manner from shear flow to dilatation failure. The results are explained by the suppressed shear transformation and enhanced cavitation effect at low temperature, which lead to the embrittlement of these Ti-based BMGs. This work provides an experimental foundation to understand and accommodate the impact behaviors of BMGs at cryogenic temperature. The as-measured impact toughness of the (Ti41Zr25Be26Ni8)93Cu7 and (Ti41Zr25Be28Fe6)91Cu9 BMGs at cryogenic temperature is relatively robust compared to other BMGs, making them promising materials in further aerospace applications.