Ti, Nb, Al及其二元合金状态方程的第一原理计算及其应用

First-principles calculation and application of Ti, Nb, Al and their binary alloy equations of state

金属状态方程对于探究金属及合金原子的相互作用中起到了至关重要的作用.本文使用第一原理计算了Ti,Nb,Al及其二元合金能量与原子间距关系(E-r关系),并使用得到的E-r关系计算了金属及合金的体弹性模量,结果与实验值吻合的很好.计算结果表明,使用不同的赝势,计算不同金属表现出不同的适用性;二元合金的E-r曲线处于对应合金化元素曲线之间;并且合金的E-r曲线会更靠近合金内含量较高的元素的E-r曲线;并发现合金E-r关系可通过组成合金的纯金属的E-r关系计算获得,且用该方法计算材料的体弹性模量与实验值非常符合.

The equation of state(EOS)of the metal plays a crucial role in exploring the interatomic potentials of metals and alloys.In this paper,first-principles calculations using the VASP software package based on density functional theory were carried out.The relationships about E-r of three metals Ti,Nb,Al and their binary alloys are calculated by using different pseudopotentials.And the calculated E-r relationships are in good agreement with Rose’s results.As a verification and application,we used the obtained E-r relationship to calculate the bulk modulus,and the results are in good agreement with the experimental values.From the characteristics of the alloy E-r relationship,we found that the E-r relationship of the alloy can be calculated by the weighted average method using the pure metal E-r relationship.This work provides the theoretical data foundation for the future construction of the interatomic potentials.