Effects of carbon vacancies on the structures, mechanical properties, and chemical bonding of zirconium carbides: a first-principles study. Issue 17 (18th April 2016)

• Record Type: Journal Article
• Authors: Xie, Congwei; Oganov, Artem R.; Li, Duan; Debela, Tekalign Terfa; Liu, Ning; Dong, Dong; Zeng, Qingfeng
• Is Part Of: Physical chemistry chemical physics. Volume 18:Issue 17(2016)
• Page Start: 12299
• Page End: 12306
• Publication Date: 2016-04-18
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c5cp07724a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The distribution of carbon vacancies has a great effect on Pugh's ratio of interstitial carbides. Abstract : Interstitial carbides are able to maintain structural stability even with a high concentration of carbon vacancies. This feature provides them with tunable properties through the design of carbon vacancies, and thus making it important to reveal how carbon vacancies affect their properties. In the present study, using first-principles, we have calculated the properties of a number of stable and metastable zirconium carbides ZrC1− x ( x = 0 and 1/ n, n = 2–8) which were predicted by the evolutionary algorithm USPEX. Effects of carbon vacancies on the structures, mechanical properties, and chemical bonding of these zirconium carbides were systematically investigated. The distribution of carbon vacancies has significant influence on mechanical properties, especially Pugh's ratio. Nonadjacent carbon vacancies enhance Pugh's ratio, while grouped carbon vacancies decrease Pugh's ratio. This is explained by the changes in strength of Zr–C and Zr–Zr bonding around differently distributed carbon vacancies. We further explored the mechanical properties of zirconium carbides with impurities (N and O) by inserting N and O atoms into the sites of carbon vacancies. The enhanced mechanical properties of zirconium carbides were found.