Фазовая диаграмма системы Pu-Ta

К оглавлению: Другие диаграммы (Others phase diargams)


Pu-Ta (Plutonium-Tantalum) H.C. Baxi, H.F. Rizzo, and T.B. Massalski The assessed Pu-Ta phase diagram is based on [59Sch], [67Bow], and the present thermodynamic modeling. The thermodynamic calculation indicates that the (Ta) solid solution has a pronounced retrograde solidus; this requires experimental verification. In the present assessment, the calculated solidus has been incorporated in the assessed diagram and is indicated by a dashed line. The composition and temperature of the eutectic point are very close to pure Pu and the melting point of Pu, respectively. [70Bus] reported that for Pu-5 at.% Ta and Pu-10 at.% Ta a metastable b phase (orthorhombic) was obtained on sputtering Pu and Ta, and that the phase was stable up to 300 C (10 at.% Ta). [88Riz] studied the phases obtained on sputtering Pu-Ta alloys (15 to 83 at.% Ta). For alloys containing 15 to 24 at.% Ta, the X-ray diffraction patterns of the sputtered deposits contained no crystalline phase peaks but instead contained a single broad peak, which, on analysis, was found to arise from an amorphous solid solution. From 24 to 50 at.% Ta, a mixture of an amorphous phase and a metastable bcc (e) phase was observed, whereas sputtered alloys with greater than 50 at.% Ta contained only the metastable bcc phase. This indicates a very large metastable extension of solid solubility of Pu in (Ta). 59Sch: F.W. Schonfeld, E.M. Cramer, W.N. Miner, F.H. Ellinger, and A.S. Coffinberry, Progress in Nuclear Energy, Ser. V, Vol. 2, Pergamon Press, New York, 579-599 (1959). 67Bow: D.F. Bowerson and J.A. Leary, J. Nucl. Mater., 21, 219-224 (1967). 70Bus: R.A. Busch, Plutonium 1970 and other Actinides, W.N. Miner, Ed., AIME, New York, 1037 (1970). 88Riz: H.F. Rizzo, A.W. Echeverria, W.L. Wien, and T.B. Massalski, Mater. Sci. Eng., 98, 57 (1988). Submitted to the APD Program. Complete evaluation contains 3 figures, 5 tables, and 7 references. 1