The rate-dependent shear banding and fracture behavior of a ductile bulk metallic glass (BMG) under compressive loading are investigated in this paper. The continuous deformation process of the BMG specimens is captured by using the high-speed camera under both quasi-static and dynamic compression. Their characteristic shear banding and fracture behavior are synchronized with corresponding mechanical responses. The rate effect on initiation of shear bands is attributed to an increase in the coalescence rate of free volume. Rate-dependent shear banding behavior, i.e., the transition from multiple shear banding at lower strain rate to single shear banding at higher strain rate, are resulted from an increase in free-volume concentration level with increasing loading rate. The transition of fracture behavior from shear-dominated progressive sliding along slip planes under quasi-static compression to crack-dominated failure under dynamic compression is controlled by the patterns and time-scale of shear banding at various strain rates.

本文研究了在压缩载荷下球墨铸铁玻璃（BMG）的速率依赖性剪切带和断裂行为。通过使用高速相机在准静态和动态压缩下捕获BMG标本的连续变形过程。它们的特征剪切带和断裂行为与相应的机械响应同步。剪切带萌生的速率影响归因于自由体积聚结速率的增加。随速率变化的剪切带行为，即从较低应变率的多个剪切带到较高应变率的单个剪切带的转变，是由于自由体积浓度水平随加载速率的增加而导致的。