In-situ investigation of dislocation tangle-untangle processes in small-sized body-centered cubic Nb single crystals
In-situ investigation of dislocation tangle-untangle processes in small-sized body-centered cubic Nb single crystals
复制标题
小尺寸体心立方铌单晶位错缠结-解缠过程的原位研究
DOI：
10.1016/j.matlet.2017.03.165
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发表时间：
2017-07-01
影响因子：
3
通讯作者：
Liao, Xiaozhou
中科院分区：
文献类型：
--
作者：
Shu, Xinyu;Lu, Yan;Liao, Xiaozhou
利用原位纳米压痕透射电镜研究了小尺寸体心立方（BCC）铌单晶样品中位错的时间分辨缠结和解缠结过程。结果表明，位错在塑性变形过程中不仅可以发生缠结，而且可以解缠结，这是理论上预测的，但实验上没有观察到。位错缠结的形成是由于位错的高迁移率与高密度的固着缺陷在变形BCC晶体，而解缠结过程中产生的应力增加。在我们的实验中位错缠结的强度计算的基础上广泛使用的模型，这表明与以前的模拟很好的协议。位错缠结-解缠结过程导致小尺寸BCC金属的加工硬化和高强度。(C)2017爱思唯尔B. V.保留所有权利。
Time-resolved dislocation tangle and untangle processes in small-sized body-centered cubic (BCC) niobium single crystal samples were investigated using in-situ nanoindentation transmission electron microscopy. The results reveal that dislocations can not only undergo tangle processes but can also untangle during plastic deformation, which have been predicted theoretically but not observed experimentally. The formation of dislocation tangles is attributed to the high mobility of dislocations with a high density of sessile defects in the deformed BCC crystal, whereas the untangle process arises from increased stress. The strength of dislocation tangles in our experiments was calculated based on widely used models, which showed good agreement with previous simulations. Dislocation tangle-untangle processes lead to work-hardening and high strength in small-sized BCC metals. (C) 2017 Elsevier B.V. All rights reserved.