Фазовая диаграмма системы Gd-V

К оглавлению: Другие диаграммы (Others phase diargams)


Gd-V (Gadolinium-Vanadium) J.F. Smith and K.J. Lee The composite data indicate that the Gd-V diagram is analogous to the other rare earth-V systems for which data are available, but the Gd-V diagram shows appreciable uncertainty with regard to temperatures and compositions associated with the invariant reactions, as well as the loci of the phase boundaries. Therefore, the phase diagram was calculated. Data for the Gibbs energies of fusion of the two allotropes of Gd were generated by combining transition temperatures with heats of transition [83Cha]. Data for the fusion of bcc V were taken from the V assessment [81Smi], and data for the fusion of the hypothetical cph allotrope of V were taken from [70Kau]. An initial set of interaction parameters was generated from the limited amount of data [61Bae, 61Gsc, 66Gib, 73Sav, Gschneidner] that were available for the phase equilibria. These interaction parameters, together with interaction parameters generated in analogous manner for the other trivalent lanthanon- vanadium systems, were then plotted against atomic number, and smooth curves were drawn through the trends. Refined interaction parameters were next read from these smooth curves. Because it is widely accepted that the lanthanon series varies systematically in behavior with change in atomic number, this procedure allows the refined interaction parameters for any one binary system to be based upon the composite of available phase data for the entire group of binary systems rather than upon the limited data that may be available for an individual lanthanon-vanadium binary pair. The calculated phase diagram is based on the refined interaction parameters for the Gd-V system. The Gibbs energy functions for the formation of the competing phases in the system include these refined interaction parameters. [73Sav] showed the solubility of Gd in (V) as <0.1 at.% at all temperatures. 61Bae: N.C. Baenziger and J.L. Moriarty, Acta Crystallogr., 14, 948-950 (1961). 61Gsc: K.A. Gschneidner, Jr., Rare Earth Alloys, D. Van Nostrand Co., Inc., New York, 331 (1961). 66Gib: J.A. Gibson and G.S. Harvey, U.S. Gov. Report AFML-TR-65-430, 74 (1966). 70Kau: L. Kaufman and H. Bernstein, Computer Calculation of Phase Diagrams, Academic Press, New York, 184 (1970). 73Sav: E.M. Savitskii and Yu.V. Efimov, in Redkozemel›nye Metally, Splavy I Soedineniya, Izdatel›stvo Nauka, Moscow, 310-316 (1973). 81Smi: J.F. Smith, Bull. Alloy Phase Diagrams, 2, 40-41, 172 (1981). 83Cha: M.W. Chase, Bull. Alloy Phase Diagrams, 4(1), 124 (1983). Published in Phase Diagrams of Binary Vanadium Alloys, 1989. Complete evaluation contains 1 figure, 2 tables, and 9 references. Special Points of the Gd-V System