第一性原理研究压力和温度对Ni_3Al合金力学性能、热力学性能和电子结构的影响（英文）

First-principles Study on Effect of Pressure and Temperature on Mechanical, Thermodynamic Properties, and Electronic Structure of Ni_3Al Alloy

采用基于密度泛函理论的第一性原理研究了压力和温度对Ni_3Al合金的力学性能、热力学性能和电子结构的影响。计算结果表明:弹性常数、晶格常数和弹性模量的计算值与理论值和实验值十分吻合,其中压力对弹性常数C_(11)的影响比C_(12)和C_(44)更明显,杨氏模量(E)、体模量(B)和剪切模量(G)随着压力的增加而增大。同时还对Ni_3Al合金的泊松比和各向异性因子做了分析,计算了德拜温度与压力关系。采用准谐德拜模型,预测了Ni3Al合金在压力(0～60GPa)、温度(0～1600K)下的热膨胀系数、热焓、体模量和德拜温度。最后就压力对Ni_3Al合金的态密度和电荷密度的影响做了分析。

The influence of temperature and pressure on the electronic,elastic,structural,and thermodynamic properties of Ni3Al alloy was investigated by performing a first-principles study.The calculated elastic constants,equilibrium lattice constants,and elastic modulus agree well with the recorded theoretical and experimental data.The calculated elastic constants indicate that C11 is more sensitive than C12 and C44 to pressure.The Young's modulus,bulk modulus,and shear modulus increase with the increase of pressure.The ratio of bulk to shear modulus (B/G)and anisotropy factor A were also analyzed.The Debye temperature was obtained by calculating the elastic constants,and it changes with the change in the pressure.The thermal expansion coefficient,normalized volume,heat capacity,bulk modulus,and Debye temperature ΘD were determined and analyzed using the quasi-harmonic Debye model at pressures of 0-60 GPa and temperatures of 0-1600K.Finally,the density of states and Mulliken population were investigated and the effect of pressure on these was analyzed.