npj Computational Materials

First-principles-based prediction of yield strength in the RhIrPdPtNiCu high-entropy alloy （基于第一性原理的RhIrPdPtNiCu高熵合金屈服强度预测）
Binglun Yin & William A. Curtin
npj Computational Materials 5:14 (2019)
doi:s41524-019-0151-x
Published online:05 February 2019
Abstract| Full Text | PDF OPEN

摘要:高熵合金是具有5种或5种以上组分的无规合金，各元素的比例接近于等组分, 通常能表现出优异的力学性能。在广泛的组分空间中指导新材料的设计，需要通过从头算方法计算必要的基础材料参数。本研究将密度泛函理论用于计算fcc贵金属RhIrPdPtNiCu中的元素错配体积、合金晶格常数、弹性常数和稳定的堆垛层错能。然后将这些计算结果应用于新近的温度和应变率依赖性屈服强度理论。发现无参数预测得到的583 MPa屈服强度与测量值527 MPa非常一致。在没有任何实验输入的情况下，合金成分和屈服强度之间的定量联系，使得这种基于密度泛函理论的方法路径，可与第一原理化学精度法结合，探索新的有潜力的高强度高熵合金，科研是是本研究中的合金体系，也可以是其他合金体系。　　

Abstract:High-entropy alloys are random alloys with five or more components, often near equi-composition, that often exhibit excellent mechanical properties. Guiding the design of new materials across the wide composition space requires an ability to compute necessary underlying material parameters via ab initio methods. Here, density functional theory is used to compute the elemental misfit volumes, alloy lattice constant, elastic constants, and stable stacking fault energy in the fcc noble metal RhIrPdPtNiCu. These properties are then used in a recent theory for the temperature and strain-rate dependent yield strength. The parameter-free prediction of 583MPa is in excellent agreement with the measured value of 527MPa. This quantitative connection between alloy composition and yield strength, without any experimental input, motivates this general density functional theory-based methodological path for exploring new potential high-strength high-entropy alloys, in this and other alloy classes, with the chemical accuracy of first-principles methods.

Editorial Summary

High entropy alloy: yield strength prediction（高熵合金：屈服强度预测）

该研究提出了一种新的通用方法，不依赖于任何拟合参数，实现了屈服强度的预测。来自瑞士洛桑联邦理工学院多尺度力学模型实验室及国家计算设计与发现新材料中心的尹冰轮博士等，提出了一种通用的方法。根据新近提出的溶质强化模型理论，利用密度泛函理论（DFT）计算出模型所需要的材料基本属性，然后通过模型理论准确地预测出任何随机合金（包括高熵合金）的屈服强度。DFT计算的物理量包括随机合金中各元素的平均错配体积、合金晶格常数、弹性常数和稳定的堆垛层错能。该方法预测的贵金属高熵合金RhIrPdPtNiCu屈服强度583 MPa与实验测得的强度527 MPa相当接近。同时该工作还评估了其方法中的不确定性，也评估了多种扫描组分空间的方案，以优化获得材料最高屈服强度的组分。该方法建立了合金成分与屈服强度之间的定量联系，无需实验输入，可用于探索新的、有潜力的、高强度高熵合金，并为高强度合金的“计算指导设计”提供了重要途径。

A new general method that achieves a prediction of yield strength independent of any fitting parameters. Dr. Binglun Yin, et al. from the Federal Institute of Technology in Lausanne, Switzerland, proposed a general method for performing DFT-level calculations using a newly established solute strengthening model theory to compute properties required, so that they can accurately predict the yield strength of any random alloy (including high-entropy alloy). The physical quantities calculated by DFT include the elemental misfit volumes, alloy lattice constant, elastic constants, and stable stacking fault energy. The predicted yield strength of the noble metal high-entropy alloy RhIrPdPtNiCu is 583 MPa compare to the experimentally measured 527 MPa. Meanwhile, the work also evaluated the uncertainty of the method, and a variety of scanning component space schemes to optimize the components for preparing materials with the highest yield strength. This method establishes a quantitative relationship between alloy composition and yield strength without experimental input, which can be used to explore new promising high-strength high-entropy alloys, and provides an important approach to “computation-oriented design” of high-strength alloys.