Enhanced tensile plasticity of Zr based bulk metallic glasses by a stress induced large scale flow

Tensile plasticity in a Zr-based bulk metallic glasses is achieved through a stress induced large-scale flow. The large-scale flow is activated in a complex stress field which is produced by introducing micro-pits array on specimen surfaces using a laser engraving technique. A flame-like fracture morphology with bigger size (about 10 mu m in height) is observed on the fracture surface of specimen, indicating that the size of flow here is far beyond the size of that induced by shear bands. Theoretical analysis accompanied with finite elements modeling (FEM) reveal that the form of high shear zones agrees well with that of the large-scale flow, suggesting that the flow form is changed by the complex stress field. After a comprehensive analyze, the intense shear and suppressing shear bands are concluded to be the two necessary conditions for the stress induced large scale flow. (C) 2017 Elsevier B.V. All rights reserved.