Size-dependent plasticity and fracture of a metallic glass in compression

A specimen size effect related to elastic spring-back and strain softening is reported on the deformation and fracture behavior of bulk metallic glass (BMG). Unlike in large specimens where unstable shear band propagation usually leads to catastrophic fracture, in small specimens yielding is followed by stable shear band propagation and extensive plastic deformation. Additionally, the fracture surfaces of the small specimens are smooth without the characteristic vein patterns seen in large specimens. The present results demonstrate that it is important to take specimen size into account when interpreting plasticity and fracture of BMGs, especially when considering the effects of composition on ductility.