Transition of plasticity and fracture mode of Zr-Al-Ni-Cu bulk metallic glasses with network structures

Effect of network structure on plasticity and fracture mode of Zr-Al-Ni-Cu bulk metallic glasses (BMGs) was investigated. The microstructures of transversal and longitudinal sections were exposed by chemical etching and observed by scanning electron microscopy (SEM). The mechanical properties were examined by room-temperature uniaxial compression test. The results show that both plasticity and fracture mode are significantly affected by the network structure and the alteration occurs when the size of the network structure reaches up to a critical value. When the cell size (d(c)) of the network structure is similar to 3 mu m, Zr-based BMGs characterize in plasticity that decreases with increasing dc. The fracture mode gradually transforms from single 45 degrees shear fracture to double 45 degrees shear fracture and then cleavage fracture with increasing d(c). In addition, the mechanisms of the transition of the plasticity and the fracture mode for these Zr-based BMGs are also discussed.