Фазовая диаграмма системы Pu-Th

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Pu-Th (Plutonium-Thorium) D.E. Peterson The assessed Pu-Th phase diagram is based on review of the work of [58Boc], [ 58Poo], [59Sch], [61Ell], and [67Por]. The terminal solubility of Th in (ePu) is 5.6 at.% Th at 590 C [58Boc]. [ 61Ell] estimated the upper limits of the Th solubilities in (d›Pu) and (dPu) at 1.5 and 2.6 at.% Th, respectively. The Th solubility in the a and b allotropes is assumed to be negligible. z forms peritectically. However, it was observed at temperatures of 615 [58Poo] , 610 [58Boc], and 596 C [67Por]. [58Poo] noted that the peritectic reaction is suppressed on cooling and that the z phase is formed by a nonequilibrium peritectoid reaction between (ePu) and (aTh) at about 580 C, subsequent to eutectic solidification. The transition temperature depends on the cooling rate. The sluggish nature of the peritectic reaction explains the range of transformation temperatures. Pu solubility on (bTh) extends to 49.5 с 2 at.% Th [67Por]. The terminal solubility of Pu in (aTh) is at 54 с 3 at.% Th. The presence of (bTh) is difficult to detect from metallography, because this allotrope is not retained on quenching. 58Boc: A.A. Bochvar, S.T. Konobeevskii, V.I. Kutaitsev, T.S. Men'shikova, and N.T. Chebotareve, Sov. J. At. Energy, 5, 1177 (1958); Proc. 2nd U.N. Int. Conf. on Peaceful Uses of Atomic Energy, Geneva, 1958, Vol. 6, 191 (1958). 58Poo: D.M. Poole, G.K. Williamson, and J.A.C. Marples, J. Inst Met., 86, 172 (1957-58). 59Sch: F.W. Schonfeld et al., Metallurgy and Fuels, Vol. 2, Pergamon Press, Elmsford, NY, 579-599 (1959). 61Ell: R.O.Elliott and A.C. Larson, The Metal Plutonium, A.S. Coffinberry and W.N. Miner, Ed., University of Chicago Press, Chicago, 265-280 (1961). 67Por: A.Y. Portnoff and D. Calais, J. Nucl. Mater., 24, 158 (1967). Published in Bull. Alloy Phase Diagrams, 6(3), Jun 1985. Complete evaluation contains 2 figures, 3 tables, and 10 references. Special Points of the Pu-Th System