Chemical short range order strengthening in a model FCC high entropy alloy
Chemical short range order strengthening in a model FCC high entropy alloy
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DOI：
10.1016/j.actamat.2020.02.041
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发表时间：
2020-05-15
期刊：
影响因子：
9.4
通讯作者：
Parthasarathy, T. A.
中科院分区：
文献类型：
--
作者：
Antillon, E.;Woodward, C.;Parthasarathy, T. A.
为了了解化学短程有序对FCC成分复杂合金变形机制的作用，采用混合分子动力学/蒙特卡罗模拟方法对随机模型合金（Co30-Fe16.67-Ni36.67-Ti16.67）在不同温度下进行退火。模拟结果表明，随着退火温度的降低，化学短程有序度（CSRO）显著增加。退火倾向于使高焓区均匀化，因为：(1)化学物质重新分布成更紧凑的构型，(2)原子对形成化学键，降低了系统的总能量；本文研究的成分显示了大量的有序的Ti-Fe对相对于随机分布的成对（EAM）势，由于Johnson和Zhou。能量拓扑方法用于评估随机固溶体和退火系统中的局部强化行为，其中在不匹配成分和影响总体临界分解剪切应力的化学短程顺序之间观察到有趣的相互作用。量化了短时阶对临界屈服应力的影响，并与现有的固溶体模型进行了比较。最后，我们提出并验证了Labusch-Varvenne类包含化学短程序影响的高浓度固溶分析模型的扩展。(C) 2020材料学报Elsevier Ltd.出版。版权所有。
In order to understand the role of chemical short-range order on deformation mechanisms in FCC compositionally complex alloys, a random model alloy (Co30-Fe16.67-Ni36.67-Ti16.67) is annealed at various temperatures using Hybrid Molecular-dynamics/Monte-Carlo simulations. The simulations produce significant chemical short-range order (CSRO) that increases with decreasing annealing temperature. Annealing tends to homogenize regions of high enthalpy due to: (1) chemical species redistributing into more compact configurations, and (2) pairs of atoms forming chemical bonds that lower the overall energy of the system; the composition explored here shows significant amount of ordering in Ti-Fe pairs with respect to random distributions as described by pairwise (EAM) potentials due to Johnson and Zhou. An energy topology approach is used to assess the local strengthening behavior in random solid solutions and annealed systems, where an interesting interplay is observed between misfit components and chemical short-range order affecting the overall critical resolved shear stress. The role of short-range order on the critical yield stress is quantified and compared with current solid solution models. Finally, we propose and validate an extension to the Labusch-Varvenne class of high-concentration solid-solution analytic models that incorporates the effects of chemical short range order. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.