Фазовая диаграмма системы Ag-Gd

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Ag-Gd (Silver-Gadolinium) K.A. Gschneidner, Jr. and F.W. Calderwood The assessed phase diagram for the Ag-Gd system is based primarily on the work of [72Kie], with some modifications. The melting points of Ag and Gd have been changed from 960.5 to 962 C and from 1315 to 1313 C, respectively, to agree with the accepted values of [Gschneidner]. The solid solubility of Gd in (Ag) is 0.95 at.% [70Gsc]. No information is available regarding the solubility of Ag in (Gd), or the effect of Ag on the a = b transformation in Gd. The Gd-rich portion of the present diagram (above about 90 at.% Gd) is drawn with dashed lines, because no data are available for this region. The eutectic temperature for Ag with the Ag-rich Gd compound has been raised from 780 C [72Kie] to 805 C. The stoichiometry of the Ag-rich compound is Ag51Gd14 and is indicated to have a stoichiometry range varying from about 21. 5 to 25 at.% Gd. Three intermetallic phases form in the Ag-Gd system: Ag51Gd14 (melting at 975 C), Ag2Gd (peritectic formation at 830 C), and AgGd (melting point at 1100 C). The phase diagram also shows three eutectics: Ag-Ag51Gd14 (805 C, 11 at.% Gd), Ag2Gd-AgGd (825 C, 37 at.% Gd), and AgGd-Gd (790 C, 77.5 at.% Gd). [71Bat] prepared metastable Ag-Gd alloys by vapor quenching onto substrates at -268.8 C, -195 C, and room temperature. The Ag-89 at.% Gd and Ag-94 at.% Gd alloys formed at room temperature, and alloys with Gd content greater than 53 at.% deposited at the lower temperature were amorphous. The amorphous Ag-Gd alloys were easily oxidized, and Gd2O3 lines were observed in the X-ray films of alloys annealed at 800 C. Microprobe analysis of the 67 at.% Gd-Ag alloy showed no segregation of either element in the "as deposited" state, but after annealing at 100 C, aggregates of Ag and Gd were evident. 70Gsc: K.A. Gschneidner, Jr., O.D. McMasters, D.G. Alexander, and R.F. Venteicher, Metall. Trans., 1, 1961-1971 (1970). 71Bat: P.A. Bates, J. Popplewell, and S.W. Charles, J. Phys. (Paris) Suppl., 32, Cl-567-568 (1971). 72Kie: G. Kiessler, E. Gebhardt, and S. Steeb, J. Less-Common Met., 26, 293- 298 (1972). Published in Bull. Alloy Phase Diagrams, 6(2), Apr 1985. Complete evaluation contains 1 figure, 1 table, and 20 references. 1