The effect of local chemical ordering on dislocation activity in multi-principle element alloys: A three-dimensional discrete dislocation dynamics study
The effect of local chemical ordering on dislocation activity in multi-principle element alloys: A three-dimensional discrete dislocation dynamics study
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DOI：
10.1016/j.actamat.2021.117307
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发表时间：
2021-09-27
期刊：
影响因子：
9.4
通讯作者：
El-Awady, Jaafar A.
中科院分区：
文献类型：
--
作者：
Sudmanns, Markus;El-Awady, Jaafar A.
多组分合金中强度和延展性的优异组合通常归因于位错与合金中各种溶质原子的相互作用。为了研究这些合金的机械性能的影响，有必要开发一个建模框架，能够量化这些溶质的位错网络的演变的影响。大规模的三维（3D）离散位错动力学（DDD）模拟可以提供访问这样的研究，但迄今为止没有相关的方法，目的是一个完整的表示真实的合金与任意的化学成分。在这里，我们介绍了一个配方的位错与替代溶质原子在fcc合金中的3D DDD模拟，占溶质强化引起的原子失配以及交叉滑移激活能的波动。使用这个模型，我们表明，各种CrFeCoNi基多主元素合金（MPEA）的化学成分的局部波动导致缓慢的位错运动，频繁的交叉滑移和对齐的位错与溶质聚集功能，解释相关的机械行为和位错活动的实验观察。它还表明，这种行为观察到的某些MPEAs不能通过假设一个完美的固溶体再现。该方法也为进一步研究任何真实的任意面心立方合金的位错塑性提供了基础。(c)2021 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The exceptional combination of strength and ductility in multi-component alloys is often attributed to the interaction of dislocations with the various solute atoms in the alloy. To study these effects on the mechanical properties of such alloys there is a need to develop a modeling framework capable of quantifying the effect of these solutes on the evolution of dislocation networks. Large scale three-dimensional (3D) Discrete dislocation dynamics (DDD) simulations can provide access to such studies but to date no relevant approaches are available that aim for a complete representation of real alloys with arbitrary chemical compositions. Here, we introduce a formulation of dislocation interaction with substitutional solute atoms in fcc alloys in 3D DDD simulations that accounts for solute strengthening induced by atomic misfit as well as fluctuations in the cross-slip activation energy. Using this model, we show that local fluctuations in the chemical composition of various CrFeCoNi-based multi-principal element alloys (MPEA) lead to sluggish dislocation motion, frequent cross-slip and alignment of dislocations with solute aggregation features, explaining experimental observations related to mechanical behavior and dislocation activity. It is also demonstrated, that this behavior observed for certain MPEAs cannot be reproduced by assuming a perfect solid solution. The developed method also provides a basis for further investigations of dislocation plasticity in any real arbitrary fcc alloy with substitutional solutes. (c) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.