Severe local lattice distortion in Zr- and/or Hf-containing refractory multi-principal element alloys
Severe local lattice distortion in Zr- and/or Hf-containing refractory multi-principal element alloys
复制标题
DOI：
10.1016/j.actamat.2019.11.026
复制
发表时间：
2020-01-15
期刊：
影响因子：
9.4
通讯作者：
Zhang, Fuxiang
中科院分区：
文献类型：
--
作者：
Tong, Yang;Zhao, Shijun;Zhang, Fuxiang
虽然在新兴体心立方（BCC）难熔多主元素合金（rmpea）中发现了卓越的机械和辐射性能，但其复杂原子环境的重要性，反映了原子尺寸和化学的多样性，在原子水平上尚未得到很大程度的探索。本文采用基于原子对分布函数测量的局域结构方法，结合密度泛函理论（DFT）计算对一系列BCC rmpea进行了研究。我们的研究结果表明，所有分析的RMPEAs都在一定程度上表现出局部晶格畸变（LLD），但严重的LLD，即Hume-Rothery规则中15%原子尺寸差异的分解，只发生在含Zr和/或含hf的RMPEAs中。此外，通过DFT计算，我们发现元素之间的电荷转移在平均上深刻地降低了尺寸失配效应，从而稳定了这种能量不利的严重LLD。观察到的LLD和电荷转移之间的竞争共存表明了电子效应对rmpea中局部环境的重要性。(C) 2019材料学报Elsevier Ltd.出版。版权所有。
Whereas exceptional mechanical and radiation performances have been found in the emergent body-centered cubic (BCC) refractory multi-principal element alloys (RMPEAs), the importance of their complex atomic environment, reflecting diversity in atomic size and chemistry, has been largely unexplored at the atomic level. Here, we adopt a local structure approach based on the atomic pair distribution function measurements in combination with density functional theory (DFT) calculations to investigate a series of BCC RMPEAs. Our results demonstrate that all the analyzed RMPEAs exhibit local lattice distortions (LLD) to some extent, but a severe LLD, a breakdown of the 15% atomic size difference in Hume-Rothery rules, occurs only in the Zr- and/or Hf-containing RMPEAs. In addition, through the DFT calculations we show that charge transfer among the elements profoundly reduces the size mismatch effect in average to stabilize this energy-unfavorable severe LLD. The observed competitive coexistence between LLD and charge transfer demonstrates the importance of the electronic effects on the local environments in RMPEAs. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.