Extraordinary local structure deformation of superhard tungsten tetraboride under compression
Extraordinary local structure deformation of superhard tungsten tetraboride under compression
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超硬四硼化钨在压缩下的异常局部结构变形
DOI：
10.1016/j.jallcom.2019.152989
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发表时间：
2020-03
影响因子：
6.2
通讯作者：
Dongliang Chen
中科院分区：
文献类型：
--
作者：
Juncai Dong;Haijing Li;Zhiying Guo;Xingyu Hao;Dongliang Chen
在这项工作中，我们探索超硬材料候选人WB 4的变形机制，使用高压X射线吸收精细结构谱高达47 GPa。通过研究局部W-B键合参数随压力的变化，我们发现WB 4中存在一个特殊的两阶段变形过程。第一，突然逐步增加的W-B键的障碍与伴随的白线强度下降在1.21 GPa。这表明硼层的畸变是由W 5d电子耗尽引起的W-B键弱化引起的。这种转变可能是负责通过X射线衍射观察到的双曲轴软化。第二，在1.42GPa下，W-B键无序度显著降低。这表明硼层有变得更平坦的趋势，这可能与W-B键最大化以适应高压缩有关。这些特殊的结构重排和键合优化在其他过渡金属硼化物如ReB 2中没有观察到。我们的研究结果为WB 4中受约束的三维硼网络在压缩下承受变形的机制提供了关键见解，这可以促进具有定制机械性能的新型WB 4基材料的自下而上设计。
In this work, we explore the deformation mechanism in superhard material candidate WB4using high-pressure X-ray absorption fine structure spectroscopy up to 47 GPa. By examining the changes of local W–B bonding parameters with pressure, we find an extraordinary two-stage deformation process in WB4. First, a sudden stepwise increase of the W–B bond disorder with a concomitant drop of the white-line intensity at ∼21 GPa. It indicates the occurrence of boron layers distortion which can be initiated by W–B bond weakening due to W 5delectron depletion. This transition can be responsible for the anomalousc-axis softening as observed by X-ray diffraction. Second, a marked decrease of W–B bond disorder at ∼42 GPa. It suggests a tendency for the boron layers to become flatter, which can be associated with W–B bond maximization to accommodate high compression. These peculiar structural rearrangements and bonding optimization are not observed in other transition metal borides such as ReB2. Our findings offer key insights into the mechanism of the constrained three-dimensional boron network in WB4to withstand deformation under compression, which can facilitate the bottom-up design of novel WB4-based materials with tailored mechanical properties.
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影响因子：
--
作者：
D. Koningsberger;R. Prins
通讯作者：
D. Koningsberger;R. Prins
DOI：
10.1088/0953-8984/22/4/045701
发表时间：
2010-02
期刊：
Journal of Physics: Condensed Matter
影响因子：
--
作者：
J. Pellicer-Porres;A. Segura;Alfonso Muñoz;A. Polian;A. Congeduti
通讯作者：
J. Pellicer-Porres;A. Segura;Alfonso Muñoz;A. Polian;A. Congeduti
影响因子：
15
作者：
Mohammadi, Reza;Xie, Miao;Kaner, Richard B.
通讯作者：
Kaner, Richard B.
影响因子：
2.5
作者：
Ravel, B;Newville, M
通讯作者：
Newville, M
DOI：
10.1073/pnas.1102636108
发表时间：
2011-07-05
影响因子：
11.1
作者：
Mohammadi, Reza;Lech, Andrew T.;Kaner, Richard B.
通讯作者：
Kaner, Richard B.