Фазовая диаграмма системы Cd-Ti

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Cd-Ti (Cadmium-Titanium) J.L. Murray The equilibrium solid phases of the Ti-Cd system are (1) the cph (aTi) solid solution, which dissolves about 6.5 at.% Cd; nothing is known about the homogeneity range of the cph (Cd) solid solution; (2) the bcc (bTi) solid solution, which dissolves at least 22 at.% Cd; (3) Ti2Cd, stable up to about 850 с 50 C; and (4) TiCd, stable up to 620 C. It is extremely difficult either to prepare or heat treat Ti-Cd alloys of fixed composition. The phase diagram is nevertheless of interest because of the embrittling effect of liquid Cd on Ti. [62Cha] determined the solubility of Ti in liquid Cd. The saturated liquid and the solid in equilibrium with it were separated and chemically analyzed. They provided the following expression for the liquidus between 340 and 650 C: log NTi = 1.690 - 5.960 x 103 T-1 + 1.683 x 106 T-2, where NTi is at.% Ti and T is the temperature in K. Thermal, chemical, and X-ray analyses of crystals isolated from furnace cooled melts showed that the phases in equilibrium with the liquid are Ti2Cd above 620 C and TiCd below 620 C. [72Rob] investigated Ti-rich alloys using metallographic and X-ray techniques and chemical analysis. Heat treatments of 1 to 48 h were performed. Significant amounts of Cd were lost, and the surface layer of the alloys was entirely (aTi). The loss of Cd makes the attainment of equilibrium at a fixed composition extremely uncertain. These experiments, although carefully made, are probably accurate only for determining the temperatures of three-phase reactions. 62Cha: M.G. Chasanov, P.D. Hunt, I. Johnson, and H.M. Feder, Trans. AIME, 224, 935-939 (1962). 72Rob: W.M. Robertson, Metall. Trans., 3, 1443-1445 (1972). Published in Phase Diagrams of Binary Titanium Alloys, 1987, and Bull. Alloy Phase Diagrams, 4(4), Dec 1983. Complete evaluation contains 2 figures, 3 tables, and 3 references. Special Points of the Ti-Cd System