Фазовая диаграмма системы Au-V

К оглавлению: Другие диаграммы (Others phase diargams)


Au-V (Gold-Vanadium) J.F. Smith The assessed phase diagram for the V-Au system is based primarily on the work of [75Flu], [59War], [60Kos], [62Sto], [64Eic], and [74Ere]. Three intermediate phases occur: V3Au, VAu2, and VAu4. None of these phases melts, but rather all undergo first-order congruent solid-state transformations: V3Au to the V-rich terminal solution, and VAu2 and VAu4 to the Au-rich terminal solution. The V-rich solid solution extends from pure V to 33 с 2 at.% Au at 1385 с 5 C, where the equilibrium reaction is the peritectic decomposition of the Au-rich solid solution (39 с 1 at. % Au ) to form the V-rich solid solution and liquid (45 с 2 at.% Au). At 1244 с 5 C, the V-rich solid solution (31 с 2 at.% Au) decomposes eutectoidally to form V3Au (24 с 0.5 at.% Au) and the Au-rich solid solution (42 с 2 at.% Au). The congruent transformation of V3Au from the Cr3Si-type structure to the bcc terminal solid solution occurs at 1280 с 5 C and 22 с 1 at.% Au. V3Au is superconducting at low temperatures, and the superconducting transition temperature depends on composition and the degree of long-range atomic order. At stoichiometries near V3Au, the metastable bcc terminal solution obtained by quenching was not found to be superconducting in tests at 1 K. 59War: H. Warlimont, Z. Metallkd., 50, 708-716 (1959). 60Kos: W. Koster and H. Nordskog, Z. Metallkd., 51, 501-502 (1960). 62Sto: E. Stolz and K. Schubert, Z. Metallkd., 53, 433-444 (1962). 64Eic: H. Eicke and H.D. Hahlboh, Z. Metallkd., 55, 524-528 (1964). 74Ere: V.N. Eremenko, G.M. Lukashenko, and G.I. Khmelenko, D. Akad. Nauk Ukr. RSR, Ser. B, 36, 807-810 (1974). 75Flu: R. Flukiger, C. Susz, F. Heiniger, and J. Muller, J. Less-Common Met., 40, 103-119 (1975). Published in Phase Diagrams of Binary Gold Alloys, 1987, Phase Diagrams of Binary Vanadium Alloys, 1989, and Bull. Alloy Phase Diagrams, 2(3), Dec 1981. Complete evaluation contains 1 figure, 2 tables, and 19 references. 1