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多主元高熵合金MoNbTaVW中合金元素的 占位行为预测

发表时间:2018-12-29  浏览量:580  下载量:71
全部作者: 谢哲宇,吴波,黄锦长,杨义许,李皎亮
作者单位: 福州大学材料科学与工程学院
摘 要: 基于严格的晶体学结构信息,运用合金热力学计算模拟,理论预测了多主元高熵合金MoNbTaVW的元素占位行为随温度的变化规律。基于占位分数,建立原子在亚晶格上的分布构型,进而利用基于密度函数理论的第一性原理方法预测合金相的热力学和力学性质。MoNbTaVW合金在873~2 223 K温度范围内为BCC相。不同合金元素的占位倾向性不相同,其中Mo原子基本占据1a亚晶格位置,Nb原子基本占据1b亚晶格位置;而W、Ta和V原子在两种亚晶格位置上的占位分数随温度的变化较大,随温度的升高,W原子逐渐由1a亚晶格位置向1b亚晶格位置转移,Ta原子和V原子由1b亚晶格位置向1a亚晶格位置转移。尽管MoNbTaVW合金元素的占位情况随温度发生变化,但平衡体积随温度变化不大,体积弹性模量也相差不大,约为223 GPa,因此,MoNbTaVW合金具有高温稳定性特征。
关 键 词: 金属材料;MoNbTaVW;第一性原理计算;合金热力学;占位行为;力学性质
Title: Prediction of the element occupying behavior of multi-principal high-entropy alloy MoNbTaVW
Author: XIE Zheyu, WU Bo, HUANG Jinchang, YANG Yixu, LI Jiaoliang
Organization: College of Materials Science and Engineering, Fuzhou University
Abstract: Based on the strict crystallographic structure information, using the simulation of alloy thermodynamic calculation, the change rule with temperature-dependence of element occupying behavior in multi-principal high-entropy alloy MoNbTaVW is theoretically predicted. Based on the occupying fractions of elements, the atom occupying configuration on the sublattices is established, and the thermodynamic and mechanical properties of alloy are predicted using first-principles calculations based on density functional theory (DFT). MoNbTaVW alloy shows BCC phase in the temperature range from 873 K to 2 223 K. The site preferences of different alloying atoms are quite different. Mo atoms basically occupy sublattice 1a, Nb atoms basically occupy sublattice 1b. While occupying fractions of W, Ta and V atoms in these two sublattices are greatly dependent on the heat treatment temperature. With the increase of temperature, W atoms gradually transfer from sublattice 1a to sublattice 1b, while Ta and V atoms gradually transfer from sublattice 1b to sublattice 1a. Although the occupying behaviors of MoNbTaVW alloy change with the heat treatment temperature, the equilibrium volume and bulk elastic modulus change little at different temperatures, which the bulk elastic modulus is about 223 GPa. As a result, MoNbTaVW high entropy alloy has good temperature stability.
Key words: metallic materials; MoNbTaVW; first-principles calculations; alloy thermodynamics; occupying behavior; mechanical properties
发表期数: 2018年12月第24期
引用格式: 谢哲宇,吴波,黄锦长,等. 多主元高熵合金MoNbTaVW中合金元素的 占位行为预测[J]. 中国科技论文在线精品论文,2018,11(24):2417-2424.
 
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