Predicting β′ precipitate morphology and evolution in Mg–RE alloys using a combination of first-principles calculations and phase-field modeling
Predicting β′ precipitate morphology and evolution in Mg–RE alloys using a combination of first-principles calculations and phase-field modeling
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DOI：
10.1016/j.actamat.2014.05.002
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发表时间：
2014-09
期刊：
影响因子：
9.4
通讯作者：
Yanzhou Ji;A. Issa;T. Heo;J. Saal;C. Wolverton;Long-Qing Chen
中科院分区：
文献类型：
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作者：
Yanzhou Ji;A. Issa;T. Heo;J. Saal;C. Wolverton;Long-Qing Chen
采用三维相场模型和第一性原理密度泛函理论计算相结合的多尺度模拟方法对Mg-稀土二元合金中的沉淀相形态进行了预测。第一性原理计算提供了相场模型所需的所有输入参数，包括晶格参数，弹性常数，形成能和界面能。将该模型应用于Mg-Nd合金作为模型系统。采用三维相场法定量研究了等温时效过程中亚稳β′相的形貌、惯习面的形成和空间分布。预测的β′相形貌与已有的实验观察结果非常吻合。还使用Orowan方程评估了沉淀物形态对力学性能的影响。研究结果为镁合金获得理想的析出相形态和力学性能提供了指导。
The precipitate morphology in Mg–rare earth (RE) element binary alloys is predicted using a multi-scale modeling approach combining a three-dimensional (3-D) phase-field model and first-principles density functional theory calculations. First-principles calculations provide all the required input parameters for the phase-field model, including lattice parameters, elastic constants, formation energies and interfacial energies. This integrated model is applied to a Mg–Nd alloy as a model system. Quantitative 3-D phase-field simulations are performed to study the metastable β′ precipitate morphologies, habit plane formation and spatial distribution of the precipitates during isothermal aging. The predicted morphologies of β′ precipitates are in excellent agreement with existing experimental observations. The influence of the precipitate morphology on the mechanical properties is also evaluated using the Orowan equation. The results are expected to provide guidance for achieving desirable precipitate morphologies and thus mechanical properties in Mg alloys.