Фазовая диаграмма системы Dy-Tl

К оглавлению: Другие диаграммы (Others phase diargams)


Dy-Tl (Dysprosium-Thallium) S. Delfino, A. Saccone, A. Palenzona, and R. Ferro The assessed phase diagram for the Dy-Tl system is based on the work of [ 88Sac1]. The melting points of the pure metals and the transformation temperatures have been adjusted slightly to conform to the currently accepted values. There are six intermediate phases in the assessed diagram (Dy2Tl, Dy5Tl3, Dy5Tl3+x, DyTl, Dy3Tl5, and DyTl3), four eutectic reactions, and a eutectoid reaction. The eutectoid reaction-decomposition of (bDy) into (aDy) and Dy2Tl- occurs at about 985 C. Metallography results suggest a homogeneity range of about 1 at.% for the intermediate phases, except for DyTl3 (4 to 5 at.% Tl for DyTl). Dy2Tl and Dy3Tl5 form peritectically at 1190 and 1000 C, respectively. Dy5Tl3, DyTl, and DyTl3 melt congruently at 1340, 1300, and 940 C, respectively. The formation mechanism of Dy5Tl3+x, whose powder photograph showed clear similarities with that of the Ba5Pb3-type structure, was not determined. For this phase, [87Sab] suggests a stoichiometry closer to 5:4. No experimental crystal structure data have been reported. The maximum solid solubility of Tl in (bDy) is about 5 at.% at the 1015 C eutectic temperature; the solubility in (aDy) has not been determined. The solid solubility of Dy in (bTl) and (aTl) is assumed to be negligible. Thermodynamics and magnetic properties of Dy-Tl alloys as well as the general properties of RE-Tl alloys have been discussed by [88Sac2]. 87Sab: N.A. Sabirzyanov, S.P. Yatsenko, and V.I. Kononenko, Izv. Akad. Nauk. SSSR, Met., 6, 168 (1987). 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