Фазовая диаграмма системы Sc-W

К оглавлению: Другие диаграммы (Others phase diargams)


Sc-W (Scandium-Tungsten) S. Pandian, S.V. Nagender Naidu, and P. Rama Rao The Sc-W phase diagram is a simple eutectic type with negligible terminal solid solubilities. The assessed phase diagram is based on [66Den] and [72Ack]. The solubility data of W in liquid Sc reported by [66Den] are 1.33 at.% W at 1539 C, 2.42 at.% W at 1647 C, 2.14 at.% W at 1695 C, 2.75 at.% W at 1856 C, 4.62 at.% W at 1981 C, and 7.86 at.% W at 2045 C. Assuming that there would not be a big change in the solubility value from 1539 C [66Den] to the presently accepted eutectic temperature of 1510 C, the same composition value of 1.33 at.% W could be suggested as the eutectic composition at 1510 C. However, the eutectic composition of 1.33 at.% W from the data of [66Den] is lower than 2.7 at.% W reported by [72Ack]. Both [66Den] and [72Ack] used high-purity materials and claimed high accuracy in the temperature measurement. Hence, in the present evalu- ation, an average value of 2.0 at.% W is suggested for the eutectic composition. No information is available in the literature on the solid solubility of W in ( Sc). [65Tay] established the solubility of Sc in (W) at 1625 C to be below 40 ppm. 65Tay: A. Taylor, W.M. Hickam, and N.J. Doyle, J. Less-Common Met., 9, 214-232 (1965). 66Den: D.H. Dennison, M.J. Tschetter, and K.A. Gschneidner, Jr., J. Less- Common Met., 11, 423-435 (1966). 72Ack: R.J. Ackermann and E.G. Rauh, High Temp. Sci., 4, 272-282 (1972). Published in J. Alloy Phase Diagrams, 4(2), May 1988. Complete evaluation contains 2 figures, 3 tables, and 21 references. Special Points of the Sc-W System