Фазовая диаграмма системы Gd-Tl

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Gd-Tl (Gadolinium-Thallium) S. Delfino, A. Saccone, A. Palenzona, and R. Ferro The assessed Gd-Tl phase diagram is based on the work of [83Del] as partially revised by [88Sac1]. The melting points of the pure metals and the transformation temperatures have been adjusted slightly to conform to the currently accepted values. The Gd-Tl equilibrium diagram has six intermediate phases (Gd2Tl, Gd5Tl3, Gd5Tl3+x, GdTl, Gd3Tl5, and GdTl3), four eutectic reactions, and a eutectoid reaction. The eutectoid reaction (decomposition of (bGd) into (aGd) and Gd2Tl) is speculated to occur at about 870 C. Metallography results suggest a homogeneity range of about 1 at.% for the intermediate phases, except for GdTl3. Gd2Tl and Gd3Tl5 form peritectically at 1055 and 1050 C, respectively. Gd5Tl3, GdTl, and GdTl3 melt congruently at 1220, 1270, and 990 C, respectively. The formation mechanism of the Gd5Tl3+x phase, whose powder photograph showed clear similarities with that of the Ba5Pb3-type structure, was not determined. The maximum solid solubility of Tl in (bGd) is about 16 at.% at the 920 C eutectic temperature; the solubility in (aGd) has not been determined. The solid solubility of Gd in (bTl) and (aTl) is assumed to be negligible. Thermodynamics and magnetic properties of Gd-Tl alloys as well as the general properties of RE-Tl alloys have been discussed by [88Sac2]. 83Del: S. Delfino, A. Saccone, and R. Ferro, Z. Metallkd., 74, 674 (1983). 88Sac1: A. Saccone, S. Delfino, G. Cacciamani, and R. Ferro, J. Less-Common Met., 136, 249 (1988). 88Sac2: A. Saccone, S. Delfino, and R. Ferro, J. Less-Common Met., 143, 1 ( 1988). Submitted to the APD Program. Complete evaluation contains 1 figure, 1 table, and 5 references. 1