Influences of Strain Rates on Fracture Mechanism and Phase Separation in Hf-Based Bulk Metallic Glass

The uniaxial compressive fracture behavior of a Hf44.5Cu27Ni13.5Ti5Al10 bulk metallic glass (BMG) was investigated at different strain rates (10−4∼103 s−1) by an INSTRON-5569 testing machine and Split Hopkinson Pressure Bar. The results show that the Hf44.5Cu27Ni13.5Ti5Al10 bulk metallic glass isn't sensitive to strain rate under the quasi-static compression condition. The fracture strength is 2400 MPa. The fracture strength is 2840 MPa under the dynamic compression. The dimple structure and periodical corrugation formed at the fracture surface were observed. The fracture mechanism attributed to ductile fracture in the range of micro-scale. In addition, interaction of elastic waves and the dynamic crack front plays an important role during the formation of periodic corrugations. The higher fracture stress and adiabatic temperature are caused by the higher dynamic compressive strain rate. Phase separation was formed by segregation and diffusion at the interface during compression and affected the formation of shear cracks/bands.