论文标题
V-N系统中压力诱导的结构，相变，机械和电子特性的理论研究
Theoretical study of the pressure-induced structure, phase transition, mechanical and electronic properties in the V-N system
论文作者
论文摘要
V-N系统中的稳定化合物被系统地搜索，并发现了四个新的高压阶段，包括C2/M-V $ _9 $ N，PBAM-V $ _5 $ N $ N $ _2 $，PNMA-V $ _2 $ N和I4/MCM-VN $ _2 $ _2 $。 v $ _2 $ n经历一个相位从$ \ varepsilon $ -fe $ _2 $ n-type v $ _2 $ n（p $ \ bar {3} $ 1M）到10 gpa和fe $ c-_2 $ c-c-_2 $ n（pbcn）an （PNNM）在59 GPA，然后在96 GPA时至PNMA-V $ _2 $ n。理论上证明了低温四方VN属于太空集团P $ \ bar {4} $ 200M。 WC型VN的估计维克斯硬度和断裂韧性分别为37 GPA和4.3-6.1 MPa M $^{1/2} $。 Al $ _2 $ Cu-Type VN $ _2 $（I4/MCM），维克硬度为25-27 GPA，裂缝韧性为3.6-6.6 MPa M $^{1/2} $也显示出极好的机械属性。从IVB组（Ti，Zr和HF），VB组（V，NB和TA）和VIB（CR，MO和W）的WC型单硝基的弹性性能进行了比较和比较。键强度和结构构型都决定了材料的机械性能。
Stable compounds in the V-N system are systematically searched and four new high-pressure phases are found, including C2/m-V$_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.
