Zr70Ni16Cu6Al8 bulk metallic glass (BMG) shows a clear tensile plastic deformation under high strain rate condition. In the present study, in order to investigate the tensile plastic deformation behavior of the BMG, the deformation behavior and fracture surface were observed by using high speed video camera and scanning electron microscope (SEM), respectively. As the results, it was found that the tensile plastic deformation of the BMG was induced by the specimen sliding deformation along one main shear band. Also, it was surmised that the main shear band completely penetrated the specimen, and there was viscous medium within main shear band. Furthermore, from a detailed analysis of SEM observation, it was confirmed that there were two distinct regions on the fracture surface. The first region was no-feature region and it corresponds to progressive siding of specimen along main shear band. The second region was covered with well-developed Vein pattern and it was caused as the result of a fast separation of specimen by an interaction of shear and normal force.
