Discovering novel VC1−x compounds through hybrid first-principles and evolutionary algorithms. Issue 15 (November 2016)

• Record Type: Journal Article
• Authors: Xie, Congwei; Liu, Ning; Cheng, Xiang; Li, Duan; Zeng, Qingfeng
• Is Part Of: Journal of the European Ceramic Society. Volume 36:Issue 15(2016)
• Page Start: 3593
• Page End: 3599
• Publication Date: 2016-11
• Subjects: Vanadium carbide -- Ultra-high temperature ceramic -- Evolutionary algorithm USPEX -- Mechanical strength -- Atomic rearrangement; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2016.03.034
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract : Highlights: Evolutionary algorithm USPEX was performed to find potentially stable vanadium carbides. The Pnnm -V2 C is a newly discovered structure with lower energy than previously reported Pbcn -V2 C. Vanadium rearrangement results in the strengthening of mechanical strength. Abstract: VC1− x compounds, known as ultra-high temperature ceramics, are able to maintain stability in a range of chemical compositions. Herein, using evolutionary algorithm USPEX, we performed a global search for potentially stable VC1− x compounds. We have discovered two stable compounds ( P 31 12-V6 C5 and Pnnm -V2 C) and a number of near-ground-state compounds ( Fm 3 ¯ m -VC, P 43 32-V8 C7, P 1 ¯ -V5 C4, I 4 ¯ 3 m -V4 C3, Cmcm -V3 C2, and Cmcm -V3 C). The stable Pnnm -V2 C is a new structure with lower total energy than experimentally reported α -V2 C. Based on these stable and meta-stable VC1− x compounds, we have systemically investigated their structures, mechanical properties, and chemical bonding. We found that Cmcm -V3 C2 and Cmcm -V3 C display different arrangements of vanadium from other VC1− x compounds. We suggest that such rearrangement of vanadium are able to enhance mechanical strength. Most of VC1− x compounds possess very good mechanical properties, indicating that they have potential to be utilized for structural applications.