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基于密度泛函理论框架下的第一性原理离散变分(DV)和DMol方法研究了4d过渡金属元素在γ-TiAl中的择优占位行为及其Nb和Mo的合金化效应.转移能的计算结果表明Y,Zr,Nb,Mo在γ-TiAl中有Ti占位倾向,而Tc,Ru,Rh和Pb则表现为Al占位倾向.通过对差分电荷密度、Mulliken轨道集居数以及态密度的分析表明Nb和Mo可以提高杂质元素与其近邻基体元素之间的相互作用和相应原子之间的键合强度,导致较强的固溶强化效应.
Based on the first principles of discrete density variational (DV) and DMol methods under the framework of density functional theory (DFT), the dominant occupancy of 4d transition metal in γ-TiAl and the alloying effect of Nb and Mo were investigated. The calculated results show that Y, Zr, Nb and Mo have Ti occupancy tendencies in γ-TiAl, while Tc, Ru, Rh and Pb show the occupancy tendencies of Al.Through the calculation of differential charge density, Mulliken orbit aggregation, Density analysis shows that Nb and Mo can increase the interaction between the impurity element and its neighboring matrix elements and the bonding strength between the corresponding atoms, resulting in stronger solid solution strengthening effect.