Thermally activated dislocation plasticity in body-centered cubic chromium studied by high-temperature nanoindentation
Thermally activated dislocation plasticity in body-centered cubic chromium studied by high-temperature nanoindentation
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DOI：
10.1016/j.actamat.2017.08.026
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发表时间：
2017-11-01
期刊：
影响因子：
9.4
通讯作者：
Schwaiger, Ruth
中科院分区：
文献类型：
--
作者：
Choi, In-Chul;Brandl, Christian;Schwaiger, Ruth
研究了铬 (Cr) 的变形行为，目的是了解和量化体心立方 (bcc) 金属中的热激活位错塑性以及向温度/速率无关状态的转变。利用高温纳米压痕实验表征了 bcc Cr 从室温到 673 K 的变形行为。为了在高温下验证压痕方法本身，我们系统地研究了与温度相关的压痕弹性模量，该模量清楚地显示出 308 K 磁相变时的不连续性，这与文献数据在定量上一致。我们通过分析不同温度下硬度的应变率敏感行为来表征位错塑性的动力学。观察到的塑性松弛机制的特征在由热激活扭结对成核、扭结漂移或位错-杂质相互作用控制的螺旋位错迁移率的背景下进行讨论。 (C) 2017 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
The deformation behavior of Chromium (Cr) was investigated with the goal to understand and quantify the thermally-activated dislocation plasticity and the transition to the temperature-/rate-independent regime in body-centered cubic (bcc) metals. High-temperature nanoindentation experiments were utilized to characterize the deformation behavior of bcc Cr from room temperature to 673 K. To validate the indentation method itself at elevated temperatures, we systematically studied the temperature- dependent indentation elastic modulus, which clearly shows a discontinuity at the magnetic phase transition at 308 K, which is quantitatively consistent with literature data. We characterized the kinetics of dislocation plasticity by analyzing the strain-rate sensitive behavior of the hardness at different temperatures. The observed signatures of the plastic relaxation mechanisms are discussed in the context of screw dislocation mobility governed by thermally-activated kink-pair nucleation, kink-drift or dislocation-impurity interaction. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.