Фазовая диаграмма системы Al-Pu

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Al-Pu (Aluminum-Plutonium) M.E. Kassner and D.E. Peterson The assessed Pu-Al phase diagram, with a few modifications, is nearly identical to that of [68Ell], which is essentially the diagram of [62Ell]. The experimental data of [58Boc], [58Wal], and [61Ell2] were also reviewed and used to construct the assessed diagram. [83Zuk] found that metastable Pu(d) 2 at.% Al transforms to 90% a› and 10% b› ( prime indicates a supersaturation of Al) when isopressed to 10 kbar at ambient temperature. These phases are retained at ambient pressure. On heating the isopressed specimen to 90 C, a› reverts directly back to the d phase, suggesting that d is stable at least at 90 C and above. [82Hec] found that, on cooling this same metastable alloy below -130 C, a› forms, and on reheating, some d reforms below ambient temperature, indicating that stability may exist at ambient temperature. Although the evidence is not conclusive, the d phase has been retained in the assessed diagram at ambient temperature. [62Ell] found from examinations of alloy filings that had been stored at ambient temperature for 10 years that the original Pu3Al became an fcc phase. On heating above 195 C, it reverted to the tetragonal phase, suggesting the possibility of a polymorphic transformation. Although it is not indicated in either the [62Ell] or [68Ell] diagrams, this transformation has been tentatively included in the assessed diagram. The solubility of Pu in (Al) at 650 C is 1.6 at.%. It is generally believed that ~3 to 10.5 at.% Al - (dPu) solid solutions are stable at ambient temperature. [83Zuk] reported that 2 at.% Al retains the phase metastably at ambient temperature. This phase transforms martensitically to a supersaturated (aPu) solution or a› upon cooling below -130 C. Subjecting the same d phase alloy to hydrostatic compression at ambient temperature transforms it initially to b›, which then transforms to a› at higher pressures. It was also reported that this alloy can transform to a› during mechanical polishing. 56Ell: F.H. Ellinger, J. Met., 8, 1256-1259 (1956). 56Run: O.J.C. Runnalls, Can. J. Chem., 34, 133-145 (1956). 57Lar: A.C. Larson, D.T. Cromer, and C.K. Stambaugh, Acta Crystallogr., 10, 443-446 (1957). 58Boc: A.A. Bochvar, S.T. Konobeevsky, V.I. Kutaitsev, T.S. Minshikova, and N. T. Chebotarev, Proceedings of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy, 6, 184-193 (1958). 58Wal: M.B. Waldron, J. Garstone, J.A. Lee, P.G. Mardon, J.A.C. Marples, D.M. Poole, and G.K. Williamson, Proceedings of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy, 6, 162-169 ( 1958). 61Ell1: F.H. Ellinger, in The Metal Plutonium, A.S. Coffinberry and W.N. Miner, Ed., University of Chicago Press, Chicago, 284-286 (1961). 61Ell2: R.O. Elliott and A.C. Larson, in The Metal Plutonium, A.S. Coffinberry and W.N. Miner, Ed., University of Chicago Press, Chicago, 265-280 (1961). Special Points of the Pu-Al System