Fe-Ce系化合物相结构稳定性的第一性原理研究

The First-principles Study on Phase Stability of Fe-Ce Intermetallic Compounds

采用基于密度泛函理论的第一性原理方法,研究了CeFe_2、CeFe_5、Ce_2Fe_(17)三种化合物的生成焓、结合能、电子结构、弹性性能、力学性能及德拜温度。生成焓和结合能表明三种化合物均具有热力学稳定性,且Ce_2Fe_(17)具有最好的化合物形成能力;态密度图表明三种化合物的成键方式相似,成键电子主要是由Ce的6s、5p、4f轨道电子与Fe的3d轨道电子贡献;差分电荷密度图得出三种化合物均有金属键、离子键、共价键三种键构成;杨氏模量、剪切模量、德拜温度、理论硬度的大小顺序进一步得出Ce_2Fe_(17)具有最好的力学、热力学稳定性。

The enthalpy of formation and cohesive energy, electronic structure, elastic properties, mechanical properties and Debye temperature of CeFe2, CeFe5 and Ce2Fe17 were investigated by using the first principles method based on density functional theory. The enthalpy of formation and cohesive energy show that all three compounds are thermodynamic stable, and among them, Ce2Fel7 present the strongest compound forming ability; The density of states show that three compounds bond in a similar way, bonding electrons are mainly contributed by valence electrons of Ce（6s）, Ce （Sp）, Ce（4f） and Fe （3d）orbital; Electron density difference figure shows that the three compounds are all consist of metallic bond, ionic bond and covalent bond;Young＇s modulus, shear modulus, Debye temperature, hardness of theory can further get the conclusion that Ce2Fe17 has the best mechanics and thermodynamics stability.