3d过渡金属在NiAl中的占位及对键合性质的影响

通过赝势平面波方法系统地研究了3d过渡金属元素在B2-NiAl中的占位以及对键合性质的影响.通过形成能得出Sc，Ti，V 和Zn元素优先取代NiAl中的Al位，而Cr，Mn，Fe，Co和Cu优先取代Ni位.通过分析晶格常数变化量、电荷聚居数、交叠聚居数以及价电荷密度分布, 讨论了晶格畸变和键合性质的变化.结果表明: 取代Al的Sc，Ti，V和Zn元素掺杂使NiAl中晶格发生畸变，这对NiAl键合性质的变化起着重要作用，这些掺杂元素与第一近邻Ni原子产生强烈的排斥作用，形成反键，同时它们之间发生较大的电荷转 关键词： NiAl金属间化合物 3d过渡金属 第一性原理 键合性质

The site preference of 3d transition metals in NiAl and its effects on bond characters

The site preference of 3d transition metals in B2-NiAl intermetalics and its effects on bond characters are investigated by the pseudopotential plane wave method. The formation energy results show that Sc, Ti, V and Zn prefer to occupy the Al site, while Cr, Mn, Fe, Co and Cu prefer to occupy the Ni site in NiAl. By analyzing changes in crystal lattice constants, Mulliken population, overlap population and valence charge density, the crystal lattice distortion and bond characters are discussed. The results show that the lattice distortions of Sc, Ti, V and Zn doped NiAl play an important role in determining the alloy properties. The strong repulsion interaction and anti-bonds as well as charge transfer between the dopant atom and the nearest_neighbor Ni atoms are observed, which makes the fraction of covalent bonds to be decreased and the fraction of the metallic bonds to be increased by Sc, Ti, V and Zn substituting the Al sites of NiAl. The bond character changes a little by Cr, Mn, Fe, Co and Cu substituting the Ni sites of NiAl.