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从合金热力学的角度,采用四亚晶格热力学模型,辅助以第一性原理总能计算,研究了具有ThMn12原型结构的NdFe10-xCoxMo2金属间化合物中元素的占位有序化行为。结果表明,NdFe10-xCoxMo2系列合金中稀土原子Nd占据2a亚晶格,Mo占据50%的8i亚晶格,Fe和Co原子共同占据8f、8j和剩余50%的8i亚晶格,与实验结果相吻合。在三元合金中,Fe和Co原子的占位分数在8f和8j亚晶格上随温度变化不发生改变。而在四元合金中,由于Fe和Co原子在8f和8j亚晶格上局部固溶更有利于体系稳定,Fe和Co原子的占位分数在8f和8j亚晶格上随温度变化而发生变化。Co原子部分取代Fe原子而不影响体系的占位有序化行为。Fe与Co等成分的NdFe5Co5Mo2合金中Fe原子微弱趋向于占据8f亚晶格,而Co原子则微弱趋向于占据8j亚晶格。
From the viewpoint of alloy thermodynamics, the tetragonal lattice thermodynamic model is used to assist in calculating the orderly ordering of elements in the NdFe10-xCoxMo2 intermetallic compound with ThMn12 prototypical structure, which can always be calculated by the first-principles principle. The results show that rare-earth Nd atom occupies 2a sub-lattice in NdFe10-xCoxMo2 alloy, Mo occupies 50% 8i sub-lattice, and Fe and Co atoms occupy 8f, 8j and the remaining 50% 8i sub-lattice together. Match. In the ternary alloy, the occupied fraction of Fe and Co atoms does not change with temperature on 8f and 8j sublattice. However, in the quaternary alloys, the local solid solution of Fe and Co atoms in the 8f and 8j sublattices is more conducive to the system stability, and the occupancy fractions of Fe and Co atoms change with the temperature on the 8f and 8j sublattices Variety. Partial replacement of Fe atoms by Co atoms did not affect the orderly ordering behavior of the system. The Fe atoms in Fe and Co NdFe5Co5Mo2 alloys tend to occupy the 8f sub-lattice weakly while the Co atoms weakly occupy the 8j sub-lattice.