Фазовая диаграмма системы Cr-Rh

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Cr-Rh (Chromium-Rhodium) M. Venkatraman and J.P. Neumann The Cr-Rh system is characterized by broad homogeneity ranges of the (Cr) and ( Rh) terminal solid solutions and by the presence of two intermediate phases, Cr3Rh and e. The diagram closely resembles the Cr-Ir phase diagram. The assessed phase diagram is based primarily on the work of [73Wat]. Generally, the phase boundaries are estimated to have an uncertainty of с2 at.% Rh. The points on the solidus curve correspond to the temperatures at which incipient melting was observed. According to [73Wat], the uncertainty in the temperature values is approximately с10 C. The liquidus curves were not determined, but the temperature interval between the solidus and liquidus curves is probably small, because the alloys melted rather quickly after reaching the solidus temperatures. Cr3Rh has the cubic, A15-type structure. It occurs over a narrow homogeneity range of 22 to 23 at.% Rh, that is, slightly off the ideal stoichiometric composition. It forms peritectoidally at 1265 C from the (Cr) and e phase; the reaction kinetics are slow, and annealing times of several days are required for formation. The cph e phase extends over a very broad homogeneity range from approximately 30 to 80 at.% Rh. The decreasing solubility of Rh in (Cr) with decreasing temperature suggests that Cr-rich alloys may be amenable to precipitation or age hardening. 73Wat: R.M. Waterstrat and R.C. Manuszewski, J. Less-Common Met., 32, 331-343 ( 1973). Published in Bull. Alloy Phase Diagrams, 8(2), Apr 1987. Complete evaluation contains 1 figure, 2 tables, and 11 references. 1