Фазовая диаграмма системы Be-Th

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Be-Th (Beryllium-Thorium) H. Okamoto, L.E. Tanner, and D.E. Peterson The assessed Be-Th phase diagram is based on the experimental data of [54Wil] and [61Bad] and was obtained by thermodynamic modeling. Be-Th liquidus data are limited and were available only at four special points. One intermetallic compound, Be13Th, has been observed in the Be-Th system. [ 61Bad] reported that Be13Th exists in peritectic equilibrium with (bBe). The peritectic point was reported at about 0.03 at.% Th and 1330 C. The peritectic temperature of 1330 C may be too high, because the van't Hoff relation requires about 3 at.% Th solubility in (bBe). The value reported in the original diagram of [61Bad] was 0.04 at.% Th. The assessed diagram has been constructed from these limited data with the aid of thermodynamic modeling. The melting point of bBe and the bBe = aBe allotropic transformation temperature are 1289 с 5 and 1270 с 6 C, respectively [Melt]. [50Kau] reported that a 0.4 at.% (10 wt.%) Th alloy, cooled from the melt, was two phase, consisting of 5 to 10% Th compound (apparently Be13Th) and (Th), which indicates almost no solubility of Th in (Be). According to [61Bad], the solubility is less than 0.01 at.% below 1250 C. The melting point of bTh and the bTh = aTh allotropic transformation temperature are 1755 с 10 and 1360 C, respectively [86War]. The solubility of Be in (aTh) is less than 1 at.% at 1150 C, because although the lattice parameters, microstructures, and hardnesses of 1 to 5 at.% Be alloys are nearly constant, they are different from the respective values for pure Th [ 61Bad]. The melting point of Be13Th is 1930 C [61Bad]. Be13Th is not superconducting above 0.45 K [75Buc]. 49Bae: N.C. Baenziger and R.E. Rundle, Acta Crystallogr., 2(4), 258 (1949). 50Kau: A.R. Kaufmann, P. Gordon, and D.W. Lillie, Trans. ASM, 42, 785-844 ( 1950). 54Kee: J.R. Keeler, Nucl. Eng., Part I, Chem. Eng. Progr., Symp. Ser., 50(11), 57-61 (1954). 54Wil: H.A. Wilhelm, et al., Iowa State College and F. Foot, et al., Argonne National Laboratory, as quoted in [54Kee] (1954). 61Bad: T.A. Badaeva and R.I. Kuznetsova, Tr. Inst. Met., Baikova, Gosatomizdat, Moscow, 358-368 (1961) in Russian. 63Han: G.L. Hanna and D.N. Turner, U.S. At. Energy Comm. AAEC/E-102, 16 p ( 1963). 75Buc: E. Bucher, J.P. Maita, G.W. Hull, R.C. Fulton, and A.S. Cooper, Phys. Rev. B, 11(1), 440-449 (1975). 85Gol: A.I. Goldman, S.M. Shapiro, D.E. Cox, J.L. Smith, and Z. Fisk, Phys. Rev. B, 32(9), 6042-6044 (1985). 86War: J.W. Ward, P.D. Kleinschmidt, and D.E. Peterson, Handbook of the Physics and Chemistry of the Actinides, C. Keller and A. Freeman, Ed., North- Holland, Amsterdam (1986). Published in Phase Diagrams of Binary Beryllium Alloys, 1987. Complete evaluation contains 1 figure, 2 tables, and 18 references. 1