Фазовая диаграмма системы Er-V

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Er-V (Erbium-Vanadium) J.F. Smith and K.J. Lee In general, there is wide scatter among the available experimental data on the Er-V system and the expected phase equilibria. [60Lov] reported extensive immiscibility in both liquid and solid states, with a monotectic reaction near the melting temperature of V (1910 C) and a eutectic reaction somewhat below the melting temperature of Er (1529 C). [Elliott] interpreted the data of [ 60Lov] as indicating eutectic melting at 9.2 at.% V at 1495 C with the Er- rich liquid in the monotectic reaction having a composition from 27 to 37 at.% V. [Elliott] argued that there was no metallographic evidence for intermetallic compounds. [Shunk] cited data from [64Cop] that confirmed the general monotectic/ eutectic nature of the system without compounds, but placed the eutectic melting near 7.8 at.% V and 1450 C, the melting point of Er at 1497 C, and the solid solubility of V in (Er) at or below 0.65 at.%. [73Sav] showed a monotectic-eutectic system whose compositions and temperatures appear to be a compromise of the earlier data. The monotectic temperature was given as 1900 с 15 C with composition of the Er-rich liquid near 33 at.% V. Eutectically melting liquid was shown at a composition of 9.8 at.% V in equilibrium with Er-rich solid containing <0.2 at.% V and with V- rich solid at all temperatures containing >99.85 at.% V. This diagram is included in [Moffatt]. The extensive scatter among the reports implies wide variations in materials purity. Consequently, the assessed phase diagram was calculated from thermodynamic data. The temperatures and compositions for the monotectic reaction and the eutectic reaction were arbitrarily chosen as those of [73Sav], because the values are near the mid-range of the reported experimental values. An initial set of interaction parameters was evaluated by fitting in these temperatures and compositions. A refined set of interaction parameters was then generated. The melting point of Er was taken as 1529 C [Melt] with an enthalpy of fusion of 19 900 J/mol [83Cha]. Data for the hypothetical bcc <259> cph transformation of V and for the hypothetical bcc <259> L transformation of Er were taken from [70Kau] and [64Gsc]. 60Lov: B. Love, WADD Tech. Rep. 60-74 (1960); Reissued as U.S. Government Rep. AD-242706, 226 p. 64Cop: M. Copeland and H. Kato, in Physics and Materials Problems of Reactor Control Rods, IAEA, Vienna, 295-317 (1964). 64Gsc: K.A. Gschneidner, Jr., Solid State Phys. 16, 275-426 (1964). 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, Redkozemel›nye Metally, Splavy i Soedineniya, Izdatel›stvo Nauka, Moscow, 310-316 (1973) in Russian. 83Cha: M.W. Chase, Bull. Alloy Phase Diagrams, 4(1), 124 (1983). Published in Phase Diagrams of Binary Vanadium Alloys, 1989. Complete evaluation contains 2 figures, 2 tables, and 9 references. Special Points of the Er-V System