V掺杂Ni3Al点缺陷结构及合金化效应的第一性原理研究

Point Defects Structure and Alloying Effects of V Atoms into Ni3Al Alloy: a First-Principles Study

摘要:

基于密度泛函理论的第一性原理平面波赝势方法研究了V掺杂Ni3Al合金的电子结构和点缺陷结构。通过计算与实验结果对比选择了适合Ni3Al合金计算的近似方法，计算了含有各个缺陷的晶胞的晶格常数，形成热和结合能，点缺陷的形成能和平衡浓度，态密度和电荷密度。计算结果表明：Ni3Al合金中反位缺陷较空位缺陷易形成，NiAl 是Ni3Al合金中最主要的反位缺陷，Al位最易形成缺陷，在1400 K时，空位缺陷的浓度远远低于反位缺陷的浓度。V加入Ni3Al合金体系中能提高合金的稳定性。

Abstract:

Using the first-principles plane-wave pseudopotential method based on the density functional theory, the electronic structure and the point defects structure of V into Ni3Al alloy were studied. The approximate algorithm of Ni3Al alloy was selected by comparing experimental results with the calculation. The lattice constant, the formation enthalpies, cohesive energies, formation energies and equilibrium concentration of point defects, density of states of the supercell and charge density were calculated. The calculation results show that anti-site defects are more easily formed than vacancy defects, NiAl is the most important anti-site defect, and the Al-sites are the defects more easily formed than Ni-sites in the Ni3Al alloy. The equilibrium concentration of vacancy defects in Ni3Al alloy at 1400 K is far below that of the anti-site defects. V atoms into Ni3Al alloy system can increase the stability of the alloy.