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采用基于第一性原理的平面波赝势方法,研究了Nb原子在Ni3Al中的格点取代行为及合金化效应.通过对不同原子被置换后体系的形成热、结合能及电子态密度的计算和比较,发现Nb原子倾向于取代Ni3Al中的Al原子,其取代行为主要由系统的电子结构决定,计算结果与实验相符.为了进一步研究Nb原子的取代行为,对Nb原子占据的格点以松散或紧凑分布下体系的总能、形成热、结合能以及电子态密度进行了计算,结果表明Nb原子占据的格点更倾向于紧凑分布.为了研究Nb对Ni3Al的合金化效应,对Nb原子占据体系的结合能,电子态密度和电荷密度进行了计算,结果表明Nb原子的加入能提高Ni3Al的稳定性.研究表明,Nb在Ni3Al中的极限固溶度介于6.25at%—12.5at%之间.
The plane-wave pseudopotential method based on the first principle is used to study the lattice substitution behavior and alloying effect of Nb atoms in Ni3Al.Based on the calculation of the formation heat, the binding energy and the electronic density of states for different atoms after substitution The results show that the Nb atom tends to replace the Al atom in Ni3Al, the substitution behavior is mainly determined by the electronic structure of the system, and the calculated results agree well with the experiment.In order to further investigate the substitution behavior of Nb atoms, The results show that the lattice points occupied by Nb atoms tend to be compactly distributed.In order to study the alloying effect of Nb on Ni3Al, the influence of Nb atomic occupation system The results show that the addition of Nb atoms can improve the stability of Ni3Al.The results show that the limiting solubility of Nb in Ni3Al is between 6.25at% -12.5at% .