Фазовая диаграмма системы Ta-V

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Ta-V (Tantalum-Vanadium) J.F. Smith and O.N. Carlson The assessed V-Ta diagram is a composite of the currently available data [ 59Car, 60Ere, 64Nef, 69Rud, 72Sav]. There is still some uncertainty as to the exact nature of the V-rich solidus. In the present assessment, an attempt was made to determine whether an azeotropic melting minimum occurs in the pure binary system. An alloy was prepared with 11 at.% Ta. Six independent measurements yielded a melting point of 1880 C, with a mean deviation of с5 C. The melting point of the pure V base metal was determined in the same manner and was found to be 1888 с5 C. Although these melting points indicate the existence of an azeotropic melting minimum in the system, certainty is lacking. This equivocal status is not alleviated by a simple modeling calculation done with a regular solution approximation. However, on the basis of the present experimental measurements on pure materials in combination with the calculated results, a weak azeotropic minimum has been included in the assessed diagram. 59Car: O.N. Carlson, D.T. Eash, and A.L. Eustice, Reactive Metals, Vol. 2, W.R. Clough, Ed., Interscience Publishers, New York, 277-293 (1959). 60Ere: V.N. Eremenko, L.A. Tret'yanchenko, and R.D. Yankolmovich, Russ. J. Inorg. Chem., 5, 1110-1112 (1960). 64Nef: A.P. Nefedov, E.M. Sokolovskaya, A.T. Grigor'ev, I.G. Sokolova, and N.A. Nedumov, Zh. Neorg. Khim., 9, 883-887 (1964); TR: Russ. J. Inorg. Chem., 9, 486-489 (1964). 69Rud: E. Rudy, Ternary Phase Equilibria in Transition Metal-Boron-Carbon- Silicon-Systems-Part V, Compendium of Phase Diagram Data, originally published as Tech. Rep. AD 689, 843 (1969), available from NTIS as document No. AFML-TR- 65-2, Part V. 72Sav: E.M. Savitskii and Yu.V. Efimov, Monatsh. Chem., 103, 270-287 (1972). Published in Phase Diagrams of Binary Vanadium Alloys, 1989, and Bull. Alloy Phase Diagrams, 4(3), Dec 1983. Complete evaluation contains 4 figures, 4 tables, and 30 references. 1