压力对Mg₃Zn₃Y₂相的结构、电子和力学性能影响的第一性原理计算

Pressure effect on the structural, electronic, and mechanical properties of Mg₃Zn₃Y₂: A first-principles calculations

摘要:

利用基于密度泛函理论(DFT)的第一性原理计算方法,研究了高压对面心立方化合物Mg3Zn3Y2的结构,弹性和电子性能的影响。在0GPa下优化的晶格常数与其他计算和实验结果相吻合。计算并分析了Mg3Zn3Y2的弹性常数。基于弹性常数的计算结果,推导了Mg3Zn3Y2的体积模量(B),剪切模量(G),杨氏模量(E),泊松比(ν),各向异性指数(A),熔点和硬度。结果表明压力的增加可以促进Mg3Zn3Y2的力学性能。最后,通过的电子态密度的分析,表明随着压力的增加,Mg3Zn3Y2相的结构稳定性降低。

Abstract:

The first-principles calculations were performed to investigate the structural, elastic and electronic properties of typical face-centered cubic precipitate of Mg3Zn3Y2 under high pressure based on density functional theory (DFT). The optimized lattice constants at 0 GPa were similar to the other calculated and experimental results. The elastic constants of Mg3Zn3Y2 were calculated and analyzed. The bulk modulus （B）, shear modulus (G), Young''s modulus (E), Poisson''s ratio (ν), anisotropy index (A), melting points and hardness were further calculated based on the elastic constants. The calculation results showed that the mechanical properties of Mg3Zn3Y2 changed positively with the increase of pressure. In addition, the anisotropy index (A) of Mg3Zn3Y2 increased as the pressure increasing. The electronic density of states (DOS) of Mg3Zn3Y2 phase was analyzed, and it revealed that the structural stability of the phase was decreased as the increasing of pressure.