Фазовая диаграмма системы Au-Pb

К оглавлению: Другие диаграммы (Others phase diargams)

Au-Pb (Gold-Lead) H. Okamoto and T.B. Massalski The equilibrium phases of the Au-Pb system are (1) the liquid, L; (2) the fcc retrograde terminal solid solution, (Au), with a maximum solid solubility of Pb at about 0.11 at.% [46Rau]; (3) the fcc terminal solid solution, (Pb), with a maximum solid solubility of Au at about 0.2 at.%; (4) the Cu2Mg-type cubic intermetallic compound, Au2Pb, with no reported solubility; (5) the Al2Cu-type bct intermetallic compound, AuPb2, with some solid solubility (not specified); and (6) the aV3S-type tetragonal intermetallic compound, AuPb3, with no reported solid solubility. AuPb2 and AuPb3 may be unstable at low temperatures according to the present thermodynamic model. The present diagram, which includes three peritectic reactions and a eutectic reaction, is based primarily on evaluation of the work of [05Vog], [43Kub], [ 46Rau], [58Fuj], [71Bha], and [82Eva]. The L/[L + (Au)] and L/[L + (Pb)] liquidus boundaries have been calculated via thermodynamic modeling, and very good agreement with the experimental data has been obtained. Thus, the assessed liquidus curves have been drawn according to the model calculations. This involves the entire liquidus contour in this system, including the liquidus portions pertaining to the pure components and the intermetallic phases. An Au alloy with 75 at.% Pb, splat cooled on a -190 C substrate, could be made amorphous and decomposed into Pb and AuPb2 at 20 C [65Pre]. Metastable solid solutions of the Pb-rich (Pb) solid solution, with up to 10 at.% Au, could be made by splat cooling on a -196 C substrate [72Ray]. Superconducting transition temperatures of the metastable (Pb) solid solution were found to be linearly lowered at the rate of 0.07 K/at.% Au. The superconducting transition temperatures for Au2Pb, AuPb2, and AuPb3 are 1.18, 3.15, and 4.40 K, respectively. 05Vog: R. Vogel, Z. Anorg. Allg. Chem., 45, 11-23 (1905) in German. 43Kub: O. Kubaschewski, Z. Phys. Chem., 192, 292-308 (1943) in German. 46Rau: E. Raub and A. Engel, Z. Metallkd., 37, 76-81 (1946) in German. 58Fuj: Y. Fujiki, R. Suganuma, and T. Yoshida, J. Phys. Soc. Jpn., 13(8), 969- 970 (1958). 65Pre: P. Predecki, B.C. Giessen, and N.J. Grant, Trans. Metall. AIME, 233(7), 1438-1439 (1965). 71Bha: J.P. Bhattacharyya and K.A. Reynolds, J. Inst. Met., 99, 350-352 (1971). 72Ray: R. Ray, S.H. Hahn, and B.C. Giessen, Acta Metall., 20(12), 1335-1337 ( 1972). 82Eva: D.S. Evans and A. Prince, in Alloy Phase Diagrams, Proc. MRS Meeting, Boston, 1982, L.H. Bennett, T.B. Massalski, and B.C. Giessen, Ed., Elsevier North-Holland, New York (1983). Published in Phase Diagrams of Binary Gold Alloys, 1987, and Bull. Alloy Phase Diagrams, 5(3), Jun 1984. Complete evaluation contains 4 figures, 9 tables, and 65 references. 1