Correlation Between Dynamic Compressive Strength and Fracture Behaviors of Bulk Metallic Glasses

Abstract

The mechanical behaviors of Zr43.5Cu43.5Ni4Al8Nb1, Zr55.4Cu31.6Ni4Al8Nb1, Ti32.8Zr30.2Ni5.3Cu9Be22.7 (at.%) metallic glass at different strain rates were studied. For all the present alloys, the dispersion over 700 MPa was observed on the strength in the repeated dynamic compressions, which was much stronger than that of the quasi-static compressive strength. Such the dispersion of the dynamic compressive strength was well correlated with the corresponding fracture behaviors. The area of fracture surface was calculated and also showed a strong dispersion for all the fractured specimens tested at the strain rate of 500 s−1 and 1000 s−1. All the specimens showed a linear relationship between the square of dynamic compressive strength and the area of fracture surface in the dynamic compression tests. This phenomenon was mainly thought to be related to the difference of mean initial free volume concentration of different samples, stress concentration caused by the split Hopkinson pressure bar experimental setup and high sensitivity of defects under dynamic deformation. These findings were beneficial to deeply understand the effect of strain rate on the mechanical properties of the metallic glass.