Фазовая диаграмма системы Er-Tb

К оглавлению: Другие диаграммы (Others phase diargams)


Er-Tb (Erbium-Terbium) K.A. Gschneidner, Jr. and F.W. Calderwood The assessed Er-Tb phase diagram is based on the data of [73Spe], who used metallography, X-ray, and thermal analysis methods to investigate the phase equilibria. The liquidus/solidus is drawn as a single line, because the thermal arrests on both the heating and cooling curves were within 1.5 C. Er and aTb are mutually soluble over the entire composition range. The melting points of Er-Tb alloys decrease linearly with increasing Tb concentration. The solvus and solidus merge, indicating a peritectic reaction. The bcc structure begins to form at 34 at.% Tb. The transformation temperature for the bcc = cph transition is lowered linearly from 34 at.% Tb with increasing Tb content to the transition temperature of pure Tb (1289 C). No bcc = cph transition has been observed in pure Er and in alloys containing less than 34 at.% Tb. [79Shi] combined the Kaufman approach with values of the enthalpies and entropies of melting and transformation of the pure rare-earth metals and calculated the phase diagram. The peritectic point in the calculated diagram fell at a higher temperature and a higher concentration of Er than did the experimentally indicated peritectic point. 73Spe: F.H. Spedding, B. Sandeen, and B.J. Beaudry, J. Less-Common Met., 31, 1 (1973). 79Shi: G.J. Shiflet, J.K. Lee, and H.I. Aaronson, Calphad, 3, 129 (1979). Published in Bull. Alloy Phase Diagrams, 4(3), Nov 1983. Complete evaluation contains 2 figures and 5 references. 1