Фазовая диаграмма системы Cu-Pb

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Cu-Pb (Copper-Lead) D.J. Chakrabarti and D.E. Laughlin The equilibrium phases of the Cu-Pb system are (1) the liquid, which is miscible in all proportions at higher temperatures, but develops a miscibility gap below about 1000 C; (2) the fcc solid solution, (Cu); and (3) the fcc solid solution, (Pb). The assessed phase diagram is based primarily on evaluation of the work of [1897Hey], [51Kle], [52Kle], [55Pel], [55Sei], [ 56Pel], [58Gor], and [65Sch1]. Cu and Pb have very restricted mutual solubility in the solid state. The solubility of Pb in (Cu) does not exceed 0.09 at.% at 600 C, as determined by X-ray studies and microscopy. The solubility of Cu in (Pb) is probably less than 0.023 at.%, because precipitates were observed by optical microscopy in cast and rolled specimens of that composition. The liquidus in the Cu-Pb system has been studied extensively, and the results are in good accord. However, the data for the miscibility gap, including the critical point and the monotectic invariant compositions, show large scatter. Consequently, the accepted values must be taken as tentative. The accepted compositions and temperatures at invariant points in this evaluation are as follows. At the monotectic temperature (955 C), the Pb-rich liquid is 65 at.% Pb and the Cu-rich liquid is 15.5 с 0.5 at.% Pb [56Pel]. The eutectic point occurs at 0.2 at.% Pb and 326 C [1897Hey], and the critical point is at 35 с 1 at.% Pb [65Sch1, 65Sch2] and 995 с 5 C. No metastable phases have been reported in the Cu-Pb system. A possible metastable extension of the terminal solid solubility of Pb in (Cu), amounting to 3.3 to 4.0 at.%, was observed in electrolytically deposited Cu-Pb alloys. The miscibility gap boundaries in the Cu-Pb system were calculated with varying degrees of success by [65Sch2] and [80Tim]. Thermodynamic modeling calculations performed by the present evaluators satisfactorily reproduced the liquidus below the monotectic invariant temperature, but the corresponding miscibility gap boundaries were much less satisfactory. 1897Hey: C.T. Heycock and F.H. Neville, Philos. Trans. R. Soc. (London) A, 189, 25-69 (1897). 51Kle: O.J. Kleppa and J.A. Weil, J. Am. Chem. Soc.,73, 4848-4850 (1951). 52Kle: O.J. Kleppa, J. Am. Chem. Soc., 74, 6047-6051 (1952). 55Pel: E. Pelzel, Metall, 9, 692-694 (1955) in German. 55Sei: W. Seith, H. Johnen, and J. Wagner, Z. Metallkd., 46, 773-779 (1955) in German. 56Pel: E. Pelzel, Metall, 10, 1023-1028 (1956) in German. 58Gor: J.W. Gorman and G.W. Preckshot, Trans. Metall. Soc. AIME, 212, 367-373 ( 1958). 65Sch1: E. Schurmann and A. Kaune, Z. Metallkd., 56, 453-461 (1965) in German. 65Sch2: E. Schurmann and A. Kaune, Z. Metallkd., 56, 575-580 (1965) in German. 80Tim: M. Timucin, Metall. Trans. B, 11, 503-510 (1980). Published in Bull. Alloy Phase Diagrams, 5(5), Oct 1984. Complete evaluation contains 4 figures, 4 tables, and 40 references. 1