Фазовая диаграмма системы W-Y

К оглавлению: Другие диаграммы (Others phase diargams)


W-Y (Tungsten-Yttrium) S. Pandian, S.V. Nagender Naidu, and P. Rama Rao The assessed Y-W phase diagram is based on review of the limited experimental data [61Lun, 63Tay, 65Tay, 66Den]. The early reports [61Lun, 63Tay, 65Tay] of the existence of a eutectic in the Y-W system are found to be conflicting. According to [61Lun], a simple eutectic occurs at 0.5 at.% W and about 1550 C, whereas [63Tay] reported that the eutectic temperature is 1502 C (the assumed melting point of Y). However, [65Tay] did not find any evidence for the existence of a eutectic. No data are available for the solid solubility of W in (Y). [66Den] reported a maximum solubility of 0.517 at.% W in liquid Y at 2100 C. The liquidus in the assessed diagram is drawn to show that the probable eutectic lies at or just below the melting point of Y. The solubility of W in ( Y) at that temperature [66Den] is taken as the eutectic composition. Accordingly, the eutectic temperature and composition are suggested to be ~1522 C and 0.0725 at.% W. According to [61Lun], there are no intermetallic compounds. [61Lun] reported that the maximum solubility of Y in W is 1 at.%, whereas [ 63Tay] put it at 0.0002 at.% at 1585 C. [65Tay] suggested that the solid solubility of Y in (W) is less than 1 ppm at 1585 C. The existing data are found to be divergent. In view of the limited data, the solubility of Y in (W) is considered to be negligibly small. 61Lun: C.E. Lundin and D. Klodt, in The Rare Earths, F.H. Spedding and A.H. Daane, Ed., John Wiley & Sons, New York, 269-271 (1961). 63Tay: A. Taylor, Tech. Report. ASD-TDR-63-204 (AD 40934), 36 (1963). 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). Published in J. Alloy Phase Diagrams, 4(2), May 1988. Complete evaluation contains 1 figure, 3 tables, and 21 references. 1