Фазовая диаграмма системы Fe-Nb

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Fe-Nb (Iron-Niobium) E. Paul and L.J. Swartzendruber The equilibrium phases of the Fe-Nb system are (1) the liquid; (2) the Nb-rich solid solution based on bcc Nb; (3) the m phase intermetallic compound near the equiatomic composition, with a composition range of 47 to 49 at.% Nb; (4) the e phase intermetallic compound with a Laves structure near the composition Fe2Nb; (5) the Fe-rich d phase based on the high-temperature bcc allotrope of Fe; (6) the Fe-rich g phase based on the fcc allotrope of Fe; and (7) the Fe- rich a phase based on the low-temperature bcc allotrope of Fe. The assessed phase diagram is based primarily on the work of [60Gol] and [ 66Ram]. It was obtained by thermodynamic modeling of select experimental data. There is good agreement on the characteristics of the Fe-rich portion of the diagram. Considerable uncertainty remains concerning the phase relationships in the Nb-rich portion of the diagram. The Nb-rich liquidus is drawn primarily from the data of [60Gol]. The maximum solubility of Fe in (Nb) is 7.6 at.%. The solubility of Nb in (aFe) was reported to range from 0.095 to 0.330 at.% Nb at 600 to 900 C, respectively [66Abr]. The m phase is antiferromagnetic with a N‚el temperature of 275 с 7 K. The stoichiometric Laves phase was found to be weakly ferromagnetic with a Curie temperature of 10 K. 60Gol: H.J. Goldschmidt, J. Iron Steel Inst., 169-180 (1960). 66Abr: E.P. Abrahamson and S.L. Lopata, Trans. AIME, 236, 76-87 (1966). 66Ram: A. Raman, Z. Metallkd., 57, 301-305 (1966). Published in Bull. Alloy Phase Diagrams, 7(3), Jun 1986. Complete evaluation contains 3 figures, 6 tables, and 48 references. 1