Impact Factor:3.43

DOI number:10.1039/c8cp04222e

Affiliation of Author(s):材物学院

Journal:Physical Chemistry Chemical Physics

Funded by:国家自然科学基金、省自然科学基金

Abstract:Tungsten borides are a unique class of compounds with excellent mechanical properties comparable to those of traditional superhard materials. However, the in-depth understanding of these compounds is hindered by the uncertainty of their phase relations and complex crystal structures. Here, we explored the W-B system systematically by ab initio variable-composition evolutionary simulations at pressures from 0 to 40 GPa. Our calculations successfully found all known stable compounds and discovered two novel stable phases, P (4) over bar2(1)m-WB and P2(1)/m-W2B3, and three nearly stable phases, R3m-W2B5, Ama2-W6B5, and Pmmn-WB5, at ambient pressure and zero Kelvin. Interestingly, P (4) over bar 21m-WB is much harder than the known alpha and beta phases, while Pmmn-WB5 exhibits the highest hardness. Furthermore, it is revealed that the much debated WB4 becomes stable as the P6(3)/mmc (2 f. u. per unit cell) phase at pressures above similar to GPa, not at ambient pressure as reported previously. Our findings provide important insights for understanding the rich and complex crystal structures of tungsten borides, and indicate WB2, WB4, and WB5 as compounds with the most interesting mechanical properties.

Note:首次理论预测W-B体系硬度最大的结构Pmmn-WB5，后被实验证实！

First Author:赵昌明

Indexed by:Journal paper

Correspondence Author:段益峰

Discipline:Natural Science

First-Level Discipline:Physics

Document Type:J

Volume:20

Issue:38

Page Number:24665-24670

Translation or Not:no

Date of Publication:2018-10-14

Included Journals:SCI

Links to published journals:https://doi.org/10.1039/C8CP04222E