Stable fracture of a malleable Zr-based bulk metallic glass

We report a stable fracture phenomenon during the compression of a malleable Zr-based bulk metallic glass. In the process, the shear band along which the sample fails is constrained by the machine crosshead, thus causing a slow release of the stress and the elastic energy by small steps in the stress-strain curve. A novel and unique fishbone-like pattern was observed on the fracture surface after the final rupture instead of the typical vein-like pattern usually found upon catastrophic failure for metallic glasses. The formation of this pattern might be a result of the modest temperature rise during failure and the frustration of the meniscus instability in the crack tip due to stress redistribution in the constraint. This fracture behavior, where the crack propagation is at a much lower speed and the elastic energy is released in a stable way, might be suitable for studying the crack propagation process and the fracture mechanism in metallic glasses. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767327]