Фазовая диаграмма системы Fe-Ga

К оглавлению: Другие диаграммы (Others phase diargams)

Fe-Ga (Iron-Gallium) H. Okamoto The assessed phase diagram for the Fe-Ga system is primarily based on the work of [77Kos2]. The part of the diagram between ~20 and 35 at.% Ga from ~580 to 680 C is most controversial, presumably due to sluggish reactions, metastable reactions, and the magnetic transition of (aFe). The phases in the equilibrium diagram are (1) the liquid, L; (2) the fcc terminal solid solution, (gFe); (3) the bcc terminal solid solution, (aFe), with three different ordered states-a› (CsCl type), a›› (unknown type), and a›››(BiF3 type); (4) Ni3Sn-type hexagonal bFe3Ga; (5) AuCu3-type cubic aFe3Ga; (6) Al8Cl5-type rhombohedral bFe6Ga5; (7) monoclinic aFe6Ga5; (8) monoclinic or tetragonal Fe3Ga4; (9) tetragonal FeGa3; and (10) the orthorhombic terminal solid solution, (aGa). The solubility of Ga in (gFe) is limited to 2.8 at.% at 1140 C, forming the g loop or a continuous bcc phase field between (dFe) and (aFe) [65Das]. Based on the alloyability of Ga in Fe and the rollability of a 1.0 at.% Ga alloy, [ 32Kro] postulated a wide solubility range for (aFe). In the composition range higher than 20 at.% Ga, bcc (aFe) transforms to ordered a›, a››, and a›››. The existence and homogeneity limits of a›› must be corroborated, because of limited reports on this phase. All transitions between a›››, a››, a›, and (aFe) are assumed to be second order [82Kub] and are shown with hatched lines. When cooled at the rate of -5 C/min, a›› transforms to a›››, suppressing the formation of both bFe3Ga and aFe3Ga [77Kos2]. [78Tie] observed metastable phase transitions with the M”ssbauer effect in the composition range 25.7 and 28.3 at.% Ga. Originally disordered (aFe) at 20 C transforms to a››› at 180 to 260 C, to aFe3Ga at 280 to 380 C, to bFe3Ga at 610 C, and to a››› (or a›) at 630 C. A further transition to another form (probably noncubic, with at least two different Fe sites) may exist above 630 C. Metastable Fe13Ga9 may exist below ~570 C [77Kos2]. The magnetic transition temperatures of Fe-Ga alloys have been measured extensively. The rather poor agreement among the results of various investigators appears to reflect the difficulty in attaining equilibrium conditions, as well as ambiguity in defining the Curie temperature. 32Kro: W. Kroll, Metallwirtschaft, 11, 435-437 (1932) in German. 58Sch: K. Schubert, H. Breimer, R. Gohle, H.L. Lukas, H.G. Meissner, and E. Stolz, Naturwissenschaften, 45, 360-361 (1958) in German. 60Sch1: K. Schubert, T.R. Anantharaman, H.O.K. Ata, H.G. Meissner, M. Potzschke, W. Rossteutscher, and E. Stolz, Naturwissenschaften, 47, 512 (1960) in German. 60Sch2: K. Schubert, S. Bhan, W. Burkhardt, R. Gohle, H.G. Meissner, M. Potzschke, and E. Stolz, Naturwissenschaften, 47(13), 303 (1960). 64Das: C. Dasarathy, J. Iron Steel Inst. (London), 202(1), 51 (1964). 65Das: W. Dasarathy and W. Hume-Rothery, Proc. R. Soc. (London), A, 286, 141- 157 (1965). 65Mei: H.G. Meissner and K. Schubert, Z. Metallkd., 56(8), 523-530 (1965) in German. 66Lu: H.S. Lu, C.K. Liang, and H.T. Wang, Acta Phys. Sin. (China), 22(4), 429- 439 (1966) in Chinese; TR: Chin. J. Phys., 22(4), 340-348 (1966). 67Luo: H.L. Luo, Trans. AIME, 239(1), 119-120 (1967). 67Wag: H. Wagini, Z. Naturforsch. A, 22(1), 143-144 (1967) in German. 71Cou: J.J. Coude, J. Bras, and M. Fagot, Compt. Rend. B, 272, 781-784 (1971) in French. 72Kaw: N. Kawamiya, K. Adachi, Y. Nakamura, J. Phys. Soc. Jpn., 33(5), 1318- 1327 (1972). 74Mal: B. Malaman, M.J. Philippe, and B. Roques, Acta Crystallogr. B, 30(9), 2081-2087 (1974) in French. 74Phi: M.J. Philippe, B. Malaman, and B. Roques, Compt. Rend. C, 278(17), 1093- 1095 (1974) in French. 77Cou: J.J. Couderc, J. Bras, and M. Fagot, Phys. Status Solidi (a), 41, 595- 605 (1977) in French. 77Kos1: W. Koster and T. Godecke, Z. Metallkd., 68(9), 582-589 (1977) in German. 77Kos2: W. Koster and T. Godecke, Z. Metallkd., 68(10), 661-666 (1977) in German. 78Tie: K. Tiemann and J. Schmand, Z. Naturforsch., A, 33, 644-650 (1978) in German. 82Kub: O. Kubaschewski, Iron Binary Phase Diagrams, Springer-Verlag, New York, 38-43 (1982). 86Kra: AM. van der Kraan, Physica, B, 138, 55-62 (1986). Submitted to the APD Program. Complete evaluation contains 1 figure, 4 tables, and 33 references. Special Points of the Fe-Ga System