Фазовая диаграмма системы Al-Si

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Al-Si (Aluminum-Silicon) J.L. Murray and A.J. McAlister Al-Si is a simple eutectic system with two solid solution phases, fcc (Al) and diamond cubic (Si). The assessed phase diagram is based primarily on the evaluations of [08Fra], [14Rob], [28Dix], [47Sin], [55Cra], [56Mil], [57Nav], [ 61Gla], [66Kov], [68Dri], [68Loz], and [69Ber] and is calculated from Gibbs energies optimized with respect to the thermochemical and phase boundary data. Al-Si alloys are among the most important commercial alloys when they contain small additions (0.01 wt.%) of Na. These alloys are denoted "modified" and are greatly improved in microstructure and mechanical properties over the binary alloys. Cu or Mg also may be added for age hardening. The maximum solubility of Si in (Al) is 1.5 с 0.1 at.% at the eutectic temperature, and it decreases to 0.05 at.% at 300 C. The maximum solubility of Al in (Si) is 0.016 с 0.003 at.% at 1190 C, the retrograde point of the ( Si) solidus. Solubility of Si in (Al) can be greatly extended by splat quenching of the liquid. The maximum extension of the solid solubility has been placed at 11 с 1 at.% Si, using TEM work on the thinnest, and hence most rapidly cooled, portions of the sample. Unlike Al-Ge alloys, Al-Si alloys have not been reported to form metastable intermetallic compounds or glassy alloys. Metastable extensions of the equilibrium boundaries and T0 curves of equal Gibbs energies are of interest in interpreting the results of rapid solidification experiments. For Al-Si alloys, the relevent quality appears to be the intersection of the (Al) - L T0 curve and the extended (Si) liquidus; the extrapolation is less than 75 C and can be made with relative safety. 08Fra: W. Fraenkel, Z. Anorg. Chem., 58, 154-158 (1908) in German. 14Rob: C.E. Roberts, J. Chem. Soc., 105, 1383-1386 (1914). 28Dix: E.H. Dix and A.C. Heath, Trans. AIME, 78, 164-194 (1928). 47Sin: A.R.E. Singer and S.A. Cottrell, J. Inst. Met., 73, 33-54 (1947). 55Cra: C.M. Craighead, E.W. Cawthorne, and R.I. Jaffee, Trans. AIME, 203, 81- 87 (1955). 56Mil: R.C. Miller and A. Savage, J. Appl. Phys., 27, 1430-1432 (1956). 57Nav: D. Navon and V. Chernyshov, J. Appl. Phys., 27, 1430-1432 (1957). 61Gla: V. Glazov, Izv. Akad. Nauk SSSR, Otd. Teckhn. Nauk, Met. Topl., (4), 39- 42 (1961) in Russian. 66Kov: E. Kovacs-Csetenyi, C.R. Vassel, and I. Kovacs, Phys. Status Solidi, 17, K123-K126 (1966). 68Dri: M. Ye. Drits, E.S. Kadaner, and V.I. Kuz'mina, Izv. Akad. Nauk SSSR, Met., (1), 170-175 (1968) in Russian; TR: Russ. Metall., (1), 102-105 (1968). 68Loz: V.N. Lozovskii and A.I. Udyanskaya, Izv. Akad. Nauk SSSR, Neorg. Mater., 4(7), 1174-1175 (1968) in Russian; TR: Inorg. Mater., 4(7), 1030-1031 (1968). 69Ber: O. Berthon, G. Petot-Ervas, C. Petot, and P. Desre, C.R. Acad. Sci. Paris, C, 268, 1939-1942 (1969) in French. Published in Bull. Alloy Phase Diagrams, 5(1), Feb 1984. Complete evaluation contains 9 figures, 12 tables, and 73 references. Special Points of the Al-Si System