Multiscale Concurrent Atomistic-Continuum (CAC) modeling of multicomponent alloys
Multiscale Concurrent Atomistic-Continuum (CAC) modeling of multicomponent alloys
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DOI：
10.1016/j.commatsci.2021.110873
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发表时间：
2022-01
影响因子：
3.3
通讯作者：
K. Chu;Adrian Diaz;Youping Chen;T. Zhu;D. McDowell
中科院分区：
文献类型：
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作者：
K. Chu;Adrian Diaz;Youping Chen;T. Zhu;D. McDowell
在复杂的多组分系统，如固溶体合金中，强化主要由位错线和非均匀分布的溶质物种之间的动态相互作用控制。对此类多部件系统中的扩展缺陷长度尺度进行建模变得极其昂贵，从而推动了降阶方法的开发。这项工作探讨了应用并发原子连续（CAC）方法来模拟位错流动性随机合金在扩展的长度尺度。通过采用最近开发的平均原子间的潜力，平均“散装”材料在粗粒区域的反应与真正的随机溶质物种在原子尺度域的相互作用。我们证明，域分辨率过渡区的虚假应力完全消除由于CAC制定。同时，由于随机性在位错核心区域的局部应力波动的关键细节被捕获，波动应力平滑衰减到长程位错应力场响应。位错迁移率的计算，超过400 nm的线长度，计算作为一个函数的合金组合物中的模型FeNiCr系统，并比较完整的分子动力学（MD）。结果捕捉到了依赖于成分的趋势，同时将自由度减少了近40%。这种方法可以很容易地扩展到任何系统所描述的EAM潜力，并有利于在复杂的溶质环境中的大规模缺陷动力学的研究，以支持计算合金设计。
Strengthening in complex multicomponent systems such as solid solution alloys is controlled primarily by the dynamic interactions between dislocation lines and heterogeneously distributed solute species. Modeling of extended defect length scales in such multicomponent systems becomes prohibitively expensive, motivating the development of reduced order approaches. This work explores the application of the Concurrent Atomistic-Continuum (CAC) method to model dislocation mobility in random alloys at extended length scales. By employing recently developed average-atom interatomic potentials, the average “bulk” material response in coarse-grained regions interacts with true random solute species in the atomistic-scale domain. We demonstrate that spurious stresses in domain resolution transition regions are eliminated entirely due to the CAC formulation. Simultaneously, the key details of local stress fluctuation due to randomness in the dislocation core region are captured, and fluctuating stress smoothly decays to the long-range dislocation stress field response. Dislocation mobility calculations, for line lengths over 400 nm, are computed as a function of alloy composition in the model FeNiCr system and compared to full molecular dynamics (MD). The results capture the composition-dependent trends, while reducing degrees of freedom by nearly 40%. This approach can be readily extended to any system described by an EAM potential and facilitates the study of large-scale defect dynamics in complex solute environments to support computational alloy design.