Фазовая диаграмма системы Ce-Ti

К оглавлению: Другие диаграммы (Others phase diargams)

Ce-Ti (Cerium-Titanium) J.L. Murray The equilibrium solid phases of the Ti-Ce system are the solid solutions based on the pure elements-the bcc (bTi) and cph (aTi), the high- and low- temperature forms, respectively, and the bcc (dCe) and fcc (gCe), high- and low-temperature forms, respectively, of Ce in the temperature range under consideration (600 to 1800 C). The present assessment is based on the same experimental work as [74Gsc], but includes a thermodynamic calculation of the system. Experimental work was done on the Ti-rich part of the system by [57Sav], [57Tay], and [62Sav]. All investigators agree that there are no intermetallic phases and that a miscibility gap exists in the liquid phase. [57Tay] examined alloys containing up to 7.2 at.% Ce. The solubility of Ce in ( aTi) and (bTi) was less than 0.4 at.% in the range 750 to 980 C, based on microscopy and X-ray diffraction. Samples exhibited incipient melting when heated to 1343 C, but not at 1316 C, and the phase diagram therefore showed solid (Ce) in equilibrium with (bTi) up to 1330 C, that is, 590 C above the melting point of pure dCe. The work of [62Sav] corrects these difficulties. In the [62Sav] diagram, the melting point of Ce is lowered by small additions of Ti, and three-phase reactions above 800 C involve the Ce-rich liquid rather than a solid phase. Reactions at 1450 and 910 C were determined by thermal analysis and microscopy and those at 790 and 710 C by microscopy only. The assessed diagram is the result of a thermodynamic calculation. Input data were the temperatures of the three-phase reactions and the compositions of (aTi) and ( bTi) at the three-phase equilibria [62Sav]. 57Sav: E.M. Savitskii and G.S. Burkhanov, Zh. Neorg. Khim., 2(1), 2609-2616 ( 1957) in Russian; TR: J. Inorg. Chem., 2, 199-219 (1957). 57Tay: J.L. Taylor, Trans. AIME, 209, 94-96 (1957). 62Sav: E.M. Savitskii and G.S. Burkhanov, J. Less-Common Met., 4, 301-314 ( 1962) in German. 74Gsc: K.A. Gschneidner, Jr. and M.E. Verkade, IS-RIC-7, Rare-Earth Information Center, Iowa State University (1974). Published in Phase Diagrams of Binary Titanium Alloys, 1987. Complete evaluation contains 1 figure, 3 tables, and 5 references. Special Points of the Ti-Ce System