Фазовая диаграмма системы Cr-Nb

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Cr-Nb (Chromium-Niobium) M. Venkatraman and J.P. Neumann The Cr-Nb system is characterized by one congruently melting intermediate phase, Cr2Nb, which forms a eutectic with each of the terminal solid solutions, (Cr) and (Nb). The assessed phase diagram is based primarily on the work of [ 61Gol] and [69Rud]. All temperatures have been adjusted to IPTS-68. The existence of a single Laves-type phase that occurs at the stoichiometric composition Cr2Nb has been firmly established. Cr2Nb has the cubic MgCu2-type structure. However, there is evidence for a modified structure at high temperatures that has the hexagonal MgZn2-type structure. It transforms at 1585 to 1625 C [61Pan] to the low-temperature cubic form. Because its presence is tentative, Cr2Nb(HT) is indicated in the present diagram by a dashed line. 61Gol: H.J. Goldschmidt and J.A. Brand, J. Less-Common Met., 3, 44-61 (1961). 61Pan: V.M. Pan, Dop. Akad. Nauk Ukr. RSR, 332-334 (1961) in Ukrainian. 69Rud: E. Rudy, Tech. Rep. AFML-TR-65-2, 21, 127-130 (1969). Published in Bull. Alloy Phase Diagrams, 7(5), Oct 1986. Complete evaluation contains 3 figures, 3 tables, and 21 references. 1