碳化物
钽
材料科学
相(物质)
铌
钒
Crystal(编程语言)
碳化钒
碳化钽
晶体结构
结晶学
化学
冶金
有机化学
计算机科学
程序设计语言
作者
Christopher R. Weinberger,Gregory B. Thompson
出处
期刊:Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials
[Wiley]
日期:2019-09-20
卷期号:75 (5): 870-879
被引量:6
标识
DOI:10.1107/s2052520619011302
摘要
The crystal structure and composition of the zeta phase in the group VB transition metal carbides are not completely understood despite decades of experimental studies. As such, the phase rarely appears on phase diagrams of the group VB transition metal carbides. There is currently renewed interest in this phase, as tantalum carbide composites exhibit high fracture toughness in the presence of this phase. This work extends the initial computational study using density functional theory of the phase stability of the zeta phase in the tantalum carbide system, where the tantalum carbide zeta-phase crystal structure and stability were determined, to the niobium and vanadium carbides. It is shown that the zeta phases in the three systems share the same crystal structure and it is an equilibrium phase at low temperatures. The carbon atom ordering in the three different phases is explored and it is demonstrated that the zeta phase in the tantalum carbides prefers to order carbon atoms differently than in the niobium and vanadium carbide zeta phases. Finally, the properties of this crystal are computed, including elastic constants, electronic densities of states and phonon dispersion curves, to illustrate that this crystal structure is similar to other transition metal carbides.
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