Influence of Strain Rate on Compressive Deformation Behavior of a Zr-Cu-Ni-Al Bulk Metallic Glass at Room Temperature

摘要

The compressive-deformation behavior of the Zr_50.7Cu₂₈Ni₉Al_12.3 bulk metallic glass (BMG) was investigated over a wide strain-rate range at room temperature. The yield strength of the BMG studied is independent of the strain rates applied upon quasi-static loading; however, it decreases remarkably upon dynamic loading. Serrated flows and shear bands appear at low quasi-static strain rates; nevertheless, they vanish as the strain rate increases to 1.0 × 10−1 s−1. Cracks appearing on the side surface of the fractured sample after dynamic compression yield a strain-accommodation deformation mechanism upon dynamic loading. Scanning electron microscopy observations reveal that molten liquids increase on the fractured surfaces with increasing strain rate, indicating that adiabatic heating in the shear bands is enhanced as the strain rate increases.