Fragmentation of Co-Fe-Ta-B Bulk Metallic Glass

Abstract

The main limitation of bulk metallic glasses for their application as structural materials is the large brittleness under the external loading. We analyzed the failure characteristics of Co43Fe20Ta5.5B31.5(at.%) bulk metallic glass deformed in a compression at the room temperature and a low strain rate. Under loading the amorphous structure can store high elastic energy. During the failure this energy is released and the alloy breaks into small particles or powder exhibiting a fragmentation mode. The nanoscale fracture surface morphology respects the micromechanisms of failure of the amorphous structure. The fracture surface consists of a smooth mirror cleavage zone and a river pattern zone with the nanosized dimples arranged in lines respecting the periodic corrugation zones oriented perpendicular to the crack propagation direction.