arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2003.00036cond-mat.mtrl-sci
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V-N体系的压致结构、相变、力学和电学性质的理论研究

Theoretical study of the pressure-induced structure, phase transition, mechanical and electronic properties in the V-N system

Jin Zhang, Xinfeng Li, Xiao Dong, Huafeng Dong, Artem R. Oganov

摘要:

系统地寻找了V-N体系中的稳定化合物,发现了四个新的高压相:C2/m-V $_9$ N,Pbam-V $_5$ N $_2$,Pnma-V $_2$ N和I4/mcm-VN $_2$。V $_2$ N在10 GPa下经历从$\varepsilon$ -Fe $_2$ N型V $_2$ N(P $\bar{3}$ 1 m)到$ζ$ -Fe $_2$ N型V $_2$ N(Pbcn)的相变,在59 GPa下经历到Fe $_2$ C型V $_2$ N(Pnnm)的相变,然后在96 GPa下经历到Pnma-V $_2$ N的相变。理论上证明了低温四氢钒属P $\bar{4}$ 2 m空间群。WC型VN的维氏硬度和断裂韧性分别约为37 GPa和4.3-6.1 MPa m $^{1/2}$。Al $_2$ Cu型VN $_2$(I4/mcm)的维氏硬度为25-27 GPa,断裂韧性为3.6-6.6 MPa m $^{1/2}$,也显示出优异的机械性能。计算并比较了IVB族过渡金属(Ti、Zr和Hf)、VB族过渡金属(V、Nb和Ta)和VIB族过渡金属(Cr、Mo和W)WC型单氮化物的弹性性质。结合强度和结构配置决定了材料的机械性能。

英文摘要:

Stable compounds in the V-N system are systematically searched and four new high-pressure phases are found, including C2/m-V$_9$N, Pbam-V$_5$N$_2$, Pnma-V$_2$N and I4/mcm-VN$_2$. V$_2$N undergoes a phase transition from $\varepsilon$-Fe$_2$N-type V$_2$N (P$\bar{3}$1m) to $ζ$-Fe$_2$N-type V$_2$N (Pbcn) at 10 GPa and to Fe$_2$C-type V$_2$N (Pnnm) at 59 GPa, then to Pnma-V$_2$N at 96 GPa. Low-temperature tetragonal VN is theoretically proved to belong to space group P$\bar{4}$2m. The estimated Vickers hardnesses and fracture toughness of WC-type VN are around 37 GPa and 4.3-6.1 MPa m$^{1/2}$, respectively. Al$_2$Cu-type VN$_2$ (I4/mcm) with a Vickers hardness of 25-27 GPa and fracture toughness of 3.6-6.6 MPa m$^{1/2}$ also shows excellent mechanical properties. Elastic properties of WC-type mononitrides of transition metals from IVB group (Ti, Zr and Hf), VB group (V, Nb and Ta) and VIB (Cr, Mo and W) are calculated and compared. Both the bond strength and structural configuration determine the mechanical properties of a material.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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