Hardness and plastic deformation in a bulk metallic glass
Hardness and plastic deformation in a bulk metallic glass
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DOI：
10.1016/j.actamat.2004.10.023
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发表时间：
2005-02-01
期刊：
影响因子：
9.4
通讯作者：
Chattopadhyay, K
中科院分区：
文献类型：
--
作者：
Ramamurty, U;Jana, S;Chattopadhyay, K
对Pd 42 Ni 40 P18块体非晶合金的维氏硬度和塑性变形进行了实验研究。除了批量缩进行为之外。采用键合界面技术研究了压头下的变形形态及其随退火时间的变化。对于体积和界面压痕，剪切带引起的塑性变形区尺寸与压痕载荷的趋势吻合良好，从扩大空腔模型预测。然而，从压痕数据提取的屈服强度高于单轴压缩，表明压敏塑性。结果表明，无论是初生还是部分晶化的合金，都以剪切带机制发生变形，并呈现出半圆形和径向剪切带形貌。随着退火时间的增加，后者变得越来越突出。原子力显微镜的变形区域揭示了增加剪切带的高度与负载，与纳米压痕结果一致。而对于As-East合金，发现半圆形剪切带之间的间距与它们距压头尖端的距离无关。发现在退火合金中，在恒定间距的小区域之后，其线性增加。讨论了本研究对理解金属玻璃及其衍生物力学行为的意义。(C)2004 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
An experimental investigation into the Vickers hardness and associated plastic deformation in as-east and annealed Pd42Ni40P18 bulk metallic glass was conducted. In addition to the bulk indentation behavior. the deformation morphology underneath the indenter and its variation with annealing time was examined by employing the bonded interface technique. For both the bulk and the interface indentations, the trends in the shear band induced plastic deformation zone sizes with the indentation load agree well with those predicted from the expanding cavity model. However, the yield strength extracted from the indentation data is higher than that measured in uniaxial compression, indicating pressure sensitive plasticity. Results show that the as-east as well as the partiailly crystallized alloys deform appreciably through the shear band mechanism, with semi-circular and radial shear band morphologies. The latter gets increasingly prominent with increasing annealing time. Atomic force microscopy of the deformation region reveals increasing shear band heights with load, consistent with nanoindentation results. whereas the spacing between semicircular shear bands was found to be independent of their distance from the tip of the indenter for the as-east alloy. it was found to increase linearly, after a small zone of constant spacing, in the annealed alloys. Implications of this study in understanding the mechanical behavior of metallic glasses and their derivatives are discussed. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.