Фазовая диаграмма системы Al-Mn

К оглавлению: Другие диаграммы (Others phase diargams)


Al-Mn (Aluminum-Manganese) A.J. McAlister and J.L. Murray The assessed Al-Mn diagram is based on reinterpretation of select literature results [60Tay, 71God, 58Kon, 60Koc, 60Kos, 43Ohi, 33Dix], supported by recent experimental work and thermodynamic modeling by [87Mur]. On the Al-rich side, the invariant melting reactions are essentially those established by [71God] using thermal analysis (heating); the equilibrium phases are those identified by [60Tay] using X-ray diffraction (XRD). The peritectoid decomposition l = Al6Mn + m was proposed by [86Mur] to explain differential thermal analysis (heating and cooling) and XRD results and to resolve the discrepancy between [60Tay] and [71God]. The nomenclatures l and m are adopted in this assessment because of ambiguity of the previous designations. The maximum solubility of Mn in (Al) is 0.62 at.% at the eutectic temperature 658 с 1 C [33Dix, 43Phi]. Phase equilibria involving the cph e phase are based on specific heat, metallographic, and thermal analysis data of [55Kon], thermal analysis and XRD data of [60Koc], and magnetic and hardness measurements, XRD and metallographic work of [60Kos]. The Mn-rich part of the diagram is based primarily on thermal and magnetic analysis by [60Kos]. The peritectoid reaction (dMn) + (gMn) = (bMn) is a reinterpretation of the original data that is in better conformity with fundamental thermodynamic constraints of phase diagram construction. The (bMn)/(aMn) equilibria have been examined only cursorily by [60Kos]. Metastable processes in this system include: (1) a series of metastable invariant reactions involving l and y on cooling from the liquid [87Mur]; (2) extension of the solubility of Mn in (Al) by rapid solidification [70Ble]; (3) precipitation of a number of metastable "G" phases during decomposition of supersaturated (Al) [48Lit, 72Nes]; (4) formation by rapid solidification of two quasicrystalline phases having 5- and 10-fold symmetries [84She, 85Ben]; and (5) the martensitic transformation of e to a metastable ferromagnetic phase t [58Kon]. Gibbs energies for the solution phases and Al-rich compound phases were constructed by [87Mur] based on thermochemical data [85Des] and both stable and metastable phase equilibrium data. The calculated diagram is in good agreement with the assessed diagram and provides an interpretation of the complex metastable reaction sequences observed in cooling of Al-rich alloys. 33Dix: E.H. Dix, W.L. Fink, and L.A. Willey, Trans. AIME, 104, 335-352 (1933). 43Phi: H.W.L. Phillips, J. Inst. Met., 69, 275-350 (1943). 48Lit: K. Little and W. Hume-Rothery, J. Inst. Met., 521-525 (1948). 58Kon: H. Kono, J. Phys. Soc. Jpn., 13(12), 1444-1451 (1958). 60Koc: A.J.J. Koch, P. Hokkeling, M.G.v.d. Steeg, and K.J. De Vos, J. Appl. Phys., 31(5), 75S-77S (1960). 60Kos: W. Koster and E. Wachtel, Z. Metallkd., 51, 271-280 (1960). 60Tay: M.A. Taylor, Acta Metall., 8, 256-262 (1960). 70Ble: J. Bletry, J. Phys. Chem. Solids, 31, 1263-1272 (1970). 71God: T. Godecke and W. Koster, Z. Metallkd., 62(10), 727-732 (1971) in German. 72Nes: E. Nes. S.E. Naess, and R. Hoier, Z. Metallkd., 63, 248-525 (1972). 84She: D. Shechtman, R.J. Schaefer, and F.S. Biancaniello, Metall. Trans. A, 15, 1987-1997 (1984). 85Ben: L. Bendersky, Phys. Rev. Lett., 55(14), 1461-1463 (1985). 85Des: P. Desai, CINDAS Report (1985). 87Mur: J.L. Murray, A.J. McAlister, R.J. Schaefer, L.A. Bendersky, F. Biancaniello, and D.L. Moffat, Metall. Trans. A, 18, 385-392 (1987). Published in Bull. Alloy Phase Diagrams, 8(5), Oct 1987. Complete evaluation contains 6 figures, 7 tables, and 63 references. Special Points of the Al-Mn System