Фазовая диаграмма системы Mg-Y

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Mg-Y (Magnesium-Yttrium) A.A. Nayeb-Hashemi and J.B. Clark In the assessed Mg-Y phase diagram, the Mg-rich region is based on [61Miz], [ 67Mia], and [68Svi], and the remainder is based on [60Gib] and [65Smi]. In the assessed diagram, the (Mg) liquidus is based on [60Gib], [67Mia], and [ 68Svi]. The (Mg) solidus is based on [61Miz] and [67Mia]. The eutectic point is placed at 8.9 с 0.15 at.% Y and 566 с 1 C. The phase boundaries of (aY) and (bY) have not been determined, except for the (aY)/(bY) + MgY boundary reported by [60Gib], which must be confirmed. According to [60Gib], (bY) decomposes by a eutectoid reaction at 68.9 at.% Y and 775 C. [65Smi] confirmed the stoichiometry of Mg24Y5 and noted that Mg24Y5 and MgY are not strictly line compounds and show some homogeneity on the Mg-rich side of the stoichiometric composition. For this reason, in the assessed diagram they are shown as Mg24+xY5 and Mg1+xY. According to [65Smi], the maximum homogeneity ranges of Mg24+xY5 and Mg1+xY are ~3 and ~2 at.%, respectively. The phase boundaries were not determined. [74Las] investigated the nonequilibrium Mg-Y phase diagram in the Mg-rich region (0.6 to 3.6 at.% Y). They detected metastable hexagonal Mg5Y, which had been reported earlier by [57And] as a Mg-rich compound in the equilibrium phase diagram. The Mg-rich nonequilibrium phase diagram showed a metastable eutectic reaction [L = (Mg) + Mg5Y] at 563 C. [70Miz] and [83Dri] investigated precipitation in the Mg-Y solid solution during aging. According to [70Miz], it is possible that a metastable solvus line exists in this system and that the precipitation of a coherent metastable phase is responsible for the aging response of the Mg-Y solid solution. At various stages of aging of the supersaturated Mg-Y solid solution, [83Dri] observed ordering of the Mg3Cd type. According to [83Dri], with prolonged holding at the aging temperature of 250 C, a phase with a rhombic crystal lattice is formed. [73Bus] studied the magnetic properties of MgRE CsCl-type compounds in the temperature range 4.2 to 300 K with magnetic fields up to 18 kOe. MgY was found to be Pauli paramagnetic (see also [66Cha] and [83New]). [78Bus] studied the magnetic properties of Mg2RE compounds in the temperature range 1.5 to 300 K and with magnetic fields of up to 18 kOe. According to [ 78Bus], most of the Mg2RE compounds order ferromagnetically at temperatures " well below 100 K," except for Mg2La, Mg2Yb, and Mg2Y, which show Pauli paramagnetism; Mg2Sm and Mg2Eu order antiferromagnetically. 57And: K.P. Anderko, E.J. Klimek, D.W. Levinson, and W. Rostoker, Trans. ASM, 49, 778-791 (1957). 60Gib: E.D. Gibson and O.N. Carlson, Trans. ASM, 52, 1084-1096 (1960). 61Miz: D. Mizer and J.B. Clark, Trans. AIME, 221, 207-208 (1961). 64Car: P. Caro, Ann. Chim., 9, 481-507 (1964) in French. 64Kri1: P.I. Kripyakevich and V.I. Evdokimenko, Problems of the Theory and Application of Rare Earth Metals, E.M. Savitskii and V.F. Terekhova, Ed., Nauka, Moscow, 191-194 (1964). 64Kri2: P.I. Kripyakevich, V.I. Evdokimenko, and E.I. Gladyshevskii, Kristallografiya, 9(3), 410-411 (1964) in Russian; TR: Sov. Phys. Crystallogr., 9(3), 330-331 (1964). 64Kri3: P.I. Kripyakevich, V.I. Evdokimenko, and I.I. Zalutzkii, Dop. Akad. Nauk Ukr. RSR, (6), 766-769 (1964) in Russian. 65Smi: J.F. Smith, D.M. Bailey, D.B. Novotny, and J.E. Davison, Acta Metall., 13, 889-895 (1965). 66Cha: C.C. Chao and P. Duwez, J. Appl. Phys., 37(7), 2631-2632 (1966). 67Mia: D. Miannay, P. Gregoire, P. Azov, and P. Bastien, Compt. Rend. 265, Ser. C, 1107-1112 (1967) in French. 68Svi: Z.A. Sviderskaya and E.M. Padezhnova, Izv. Akad. Nauk SSSR, Met., (6), 183-190 (1968) in Russian; TR: Russ. Metall., (6), 126-130 (1968). 70Miz: D. Mizer and B. Peters, Proc. 2nd Int. Conf. Strength of Metals and Alloys, Vol. 2, ASM, Metals Park, OH, 669-674 (1970). 73Bus: K.H.J. Buschow, J. Less-Common Met., 33, 239-244 (1973). 74Las: N.F. Lashko, G.I. Morozova, L.P. Nefedova, and E.M. Nikolskaya, Izv. Akad. Nauk SSSR, Met., (6), 217-220 (1974) in Russian; TR: Russ. Metall., (6), 174-177 (1974). 78Bus: K.H.J. Buschow, R.C. Sherwood, and F.S.L. Hsu, J. Appl. Phys., 49(3), 1510-1512 (1978). 83Dri: M.E. Drits, L.L. Rokhlin, and I.E. Tarytina, Izv. Akad. Nauk SSSR, Met., (3), 111-116 (1983) in Russian; TR: Russ. Metall., (3), 101-104 (1983). 83New: D.J. Newman, J. Phys. F, Met. Phys., 13, 1511-1518 (1983). Published in Phase Diagrams of Binary Magnesium Alloys, 1988. Complete evaluation contains 1 figure, 6 tables, and 39 references. Special Points of the Mg-Y System