Effect of Ta particles on the fracture behavior of notched bulk metallic glass composites

The existence of second phase usually promotes the formation of multiple shear bands under uniaxial loading, leading to the apparent strain hardening and enhanced plasticity in bulk metallic glasses (BMGs). However, the effect of second phase on the fracture behavior of BMGs has been rarely investigated when shear banding is suppressed. In this work, the effect of Ta particles on the fracture behavior of notched bulk metallic glass composites (BMGCs) was investigated, where shear banding is suppressed due to the introduction of high triaxial stress state. With an increase in the volume fraction of Ta particles from 0 to 3.3%, the fracture strength significantly decreases from 2.70 to 1.20 GPa. Different from the vein-like patterns caused by shear banding, the fracture surface of notched BMGCs displays numerous equiaxed dimples and micro-cracks, indicating that voids nucleation and coalescence govern the fracture process. Due to the relatively weak bonding of the interface and the mechanical incompatibility between Ta particles and amorphous matrix, voids tend to nucleate at the interface during tensile deformation, giving rise to a reduction in the fracture strength of BMGCs.