Фазовая диаграмма системы Ga-Pu

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Ga-Pu (Gallium-Plutonium) D.E. Peterson and M.E. Kassner The assessed phase diagram for the Pu-Ga system is based primarily on the work of [64Ell], [67Hoc], and [76Che]. Elemental Pu exhibits six allotropes between ambient temperature and the melting point. The phase stability of these modifications is often a function of pressure and/or relatively small amounts of another element. [64Ell] identified six intermediate phases-Pu3Ga (z›), Pu5Ga3, PuGa (i), Pu2Ga3, PuGa2, and PuGa3 (m›)-that are stable at room temperature, and three phases-Pu3Ga (z), PuGa3 (m), and h-that are stable at elevated temperatures. Two additional phases, PuGa4 and PuGa6 (x), were also observed by [65Lan]. [ 67Hoc] confirmed the existence of these phases (except Pu2Ga3), as well as that of a PuGa (i›) polymorph existing at high temperatures. [76Che] confirmed all of these phases and also reported several new Ga-rich compounds at approximate compositions of Pu2Ga7, (Pu3Ga11-Pu4Ga15) and Pu2Ga15, as well as three PuGa3 and two PuGa6 modifications. [64Ell] reported no significant solubility of Ga in aPu, bPu, gPu, or d›Pu, with measured Ga solubilities in gPu and d›Pu of <0.25 at.%. They found that the maximum Ga solubilities in (dPu) and (ePu) were 12.5 and 20 at.%, respectively. [64Ell] and [67Hoc] determined that (dPu) alloys containing between 2 and 8 at. % Ga are retained to room temperature. Conversely, from examinations of samples annealed under high pressure, [76Che] concluded that retained (dPu) is metastable at atmospheric pressure and indicated that (dPu) undergoes a eutectoid decomposition at about 100 C to form aPu and a Pu2Ga compound. Phase transformations under high pressure are difficult to interpret. [65Ell], [67Gar], and [67Rou] concluded that (dPu) transforms to (aPu) under high pressures, but that the transformation is reversible at Ga concentrations above 3.3 at.% Ga. Retained (dPu) is assumed to be stable down to room temperature. 64Ell: F.H. Ellinger, C.C. Land, and V.O. Struebing, J. Nucl. Mater., 12, 226- 236 (1964). 65Ell: R.O. Elliott and K.A. Gschneidner, Jr., Los Alamos Sci. Lab. Rep. LA- 2312 (1965). 65Lan: C.C. Land, F.H. Ellinger, and K.A. Johnson, J. Nucl. Mater., 16, 87 ( 1965). 67Gar: H.R. Gardner, Plutonium 1965, Proc. 3rd Int. Conf. Plutonium, London, 1965, A.E. Kay and M.B. Waldron, Ed., Chapman and Hall, London, 118-132 (1967). 67Hoc: B. Hocheid, A. Tanon, B. Bedere, J. Despres, S. Hay, and F. Miard, Plutonium 1965, Proc. 3rd Int. Conf. Plutonium, London, 1965, A.E. Kay and M.B. Waldron, Ed., Chapman and Hall, London, 321-340 (1967). 67Rou: C. Roux, P. LeRoux, and M. Rapin, Mem. Sci., R. de Met., 62, 691-692, in French; Plutonium 1965, Proc. 3rd Int. Conf. Plutonium, London, 1965, A.E. Kay and M.B. Waldron, Ed., Chapman and Hall, London, 133-136 (1967). 76Che: N.T. Chebotarev, E.S. Smotriskaya, M.A. Andrianov, and O.E. Kostyuk, Plutonium 1975 and Other Actinides, H. Blank and R. Lindner, Ed., North- Holland, Amsterdam, 37-45 (1976). Published in Bull. Alloy Phase Diagrams, 9(3), Jun 1988. Complete evaluation contains 1 figure, 7 tables, and 27 references. Special Points of the Pu-Ga System