Ductile fracture in notched bulk metallic glasses
Ductile fracture in notched bulk metallic glasses
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有缺口的大块金属玻璃的延性断裂
DOI：
10.1016/j.actamat.2017.06.048
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发表时间：
2017-09-01
期刊：
影响因子：
9.4
通讯作者：
Li, Y.
中科院分区：
文献类型：
--
作者：
Pan, J.;Wang, Y. X.;Li, Y.
大块金属玻璃的变形通常是由高度局部化的剪切驱动的。由于这种不均匀的流动，通过快速剪切带以灾难性的脆性方式发生破坏，通常与宏观上非常有限的塑性应变相关。在这里，我们展示了金属一样的韧性断裂在Zr基BMG在张力下，一个完全相反的情况下，通过抑制剪切带。在没有剪切带的情况下，钙钛矿/空隙的成核以及随后的空隙生长和合并主导了初始塑性失效过程，使BMG显示出韧性断裂的基本特征，具有深凹坑和杯锥形态。这种韧性断裂只发生在非晶合金中，而不发生在完全结晶的对应物中。此外，发现Zr基BMG的韧性断裂的特征脱粘强度为1.75 GPa，是工程金属和合金中最高的之一。这些研究结果揭示了以前隐藏的BMG的延性行为，提出了一种替代方法，以提高BMG的延性，通过消除剪切带。(C)2017 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The deformation of bulk metallic glasses (BMGs) is generally driven by highly localized shear. Due to such inhomogeneous flow, failure occurs in a catastrophic brittle manner through rapid shear banding, often associated with very limited plastic strain macroscopically. Here, we demonstrate metal-like ductile fracture in Zr-based BMGs under tension, a completely opposite situation, by suppressing shear banding. In the absence of shear bands, nucleation of cavies/voids and subsequent void growth and coalescence dominate the initial plastic failure process, enabling BMGs to display the essential characteristics of ductile fracture, with deep dimples and cup-and-cone morphology. This ductile fracture only occurs in amorphous alloys, but not in the fully crystallized counterpart. Furthermore, the characteristic decohesion strength of the ductile fracture in Zr-based BMGs was found to be 1.75 GPa, one of the highest among engineering metals and alloys. These present findings reveal the previously hidden ductile behavior of BMGs, suggesting an alternative method to enhance the ductility of BMGs by removing shear banding. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.