Фазовая диаграмма системы C-Fe

К оглавлению: Другие диаграммы (Others phase diargams)


C-Fe (Carbon-Iron) H. Okamoto The stable Fe-C (graphite) and metastable Fe-Fe3C (cementite) equilibrium phase diagrams for 0 to 25 at.% C are based on thermodynamic calculations reported by [79Sch], [84Oht], and [85Gus]. Comparison of these calculated results with experimental data ([17Rue, 37Adc, 37Meh, 49Sta, 51Dar, 52Kit, 59Heu, 59Smi, 60Buc, 61Ben, 61Sch1, 61Sch2, 68Wad, 69Ban, 82Chi, 83Chi, 85Has]) indicates that the uncertainty of the diagrams is nearly с2 C and с0.1 at.%. The stable equilibrium phases of the Fe-C system at ambient pressure are (1) the gas, g; (2) the liquid, L; (3) bcc (dFe); (4) fcc (gFe), or austenite; (5) bcc (aFe), or ferrite; and (6) hexagonal (C), or graphite. Orthorhombic Fe3C, or cementite, is a metastable phase. In the Fe-C equilibrium phase diagram, phase boundaries are accepted primarily from [79Sch]. However, the results of [84Oht] are accepted for the (aFe) phase boundaries, because the ferromagnetic effects in (aFe) were considered in the thermodynamic functions and the agreement with the experimental data is better. The thermodynamic properties of L and Fe3C suggest that the unstable congruent melting point of Fe3C is 1252 C [79Sch, 84Oht]. The g = L + (C) transformation temperature is 2380 C [64Ver]. Short-range order in liquid Fe was reported by [67Fil] and [69Gri]. The liquid phase field comprises statistically disordered L0, bcc dFe-based Ld, fcc gFe-based Lg, and cph eFe-based Le regions. The fcc (gFe) phase can be retained at room temperature in very rapidly quenched alloys by suppressing the martensitic transformation temperature [ 78Sch, 85Tak]. In addition to cementite, numerous Fe-C compounds have been reported: FeC, Fe2C, Fe3C2, Fe4C, Fe5C2, Fe6C, Fe7C3, Fe8C, Fe20C9, Fe23C, and Fe23C6. Many are transitional phases or stabilized by impurity elements. Cubic [56Pin, 57Pin] or hexagonal [58Ska] Fe4C have been reported, but the lack of additional evidence suggests that Fe4C is probably a transitional phase. Fe5C2 (Hagg carbide or c) phase was found by [34Hag]. The monoclinic structure was determined by [63Sen]. Fe7C3 is hexagonal [64Her] or orthorhombic [69Fru], and it is found in high-pressure Fe-C phase diagrams. The orthorhombic structure is obtained by distorting the hexagonal structure slightly. There is a close relationship between the lattice parameters of the hexagonal and orthorhombic structures. A transient Fe2C phase with hexagonal (e) or orthorhombic (h) structure has been reported repeatedly. Because of the uncertainty in the composition, this phase also was called eFe3C. [72Hir] established that the structure of Fe2C is an orthorhombic distortion of hexagonal e. This was confirmed by [79Wil], [ 81Tan], and [83Kap]. Fe20C9 was proposed by [48Jac] instead of Fe2C, but [59Nag] could not confirm its existence by an electron diffraction study. "FeC" found by [50Eck] is actually hexagonal [64Her] or orthorhombic Fe7C3 [69Fru]. [63Hil] investigated the effect of pressure on the (gFe) = (aFe) + Fe3C eutectoid region at 35, 50, and 65 kbar. The Fe-C (diamond) phase diagrams were reported by [73Zhu2] and [73Zhu3] at 80 kbar and by [69Gri] at 130 kbar. The stable solid phases are (gFe), (eFe), Fe3C, Fe7C3, C (diamond), and C (graphite) at 80 kbar and (gFe), (eFe), Fe3C, Fe7C3, Fe2C, and C (diamond) at 130 kbar. At ambient pressure, Fe + C (diamond) becomes more stable than Fe + Fe3C below 580 C [73Zhu1]. The composition dependence of the Curie temperature of aFe (770 C) could not be detected because of the narrow homogeneity range of (aFe). The Curie temperature of Fe3C was reported to be between ~210 and 215 C. The Curie temperatures of transient phases are 380 C for Fe2C [53Coh], 247 C for Fe5C2 [53Coh, 66Hof], and 250 C for Fe7C3 [66Hof]. 17Rue: R. Ruer and F. Goerens, Ferrum, 14, 161-177 (1917) in German. 28Wes: A. Westgren, G. Pharagmen, and T. Negresco, J. Iron Steel Inst., 117, 383-400 (1928). 34Hag: G. Hagg, Z. Kristallogr., 89, 92-94 (1934) in German. 37Adc: F. Adcock, J. Iron Steel Inst., 135, 281-292 (1937). 37Meh: R.F. Mehl and C. Wells, Trans. AIME, 125, 429-469 (1937). 43Pet: N.J. Petch, J. Iron Steel Inst., 147, 221-227 (1943). 48Jac: K.H. Jack, Proc. R. Soc. (London), A, 195, 56-61 (1948). 49Sta: J.K. Stanley, Trans. AIME, 185(10), 752-760 (1949). 50Eck: H.C. Eckstrom and W.A. Adcock, J. Am. Chem. Soc., 72(2), 1042-1043 ( 1950). 50Jac: K.H. Jack, Acta Crystallogr., 3, 392-394 (1950). 51Dar: L.S. Darken and R.W. Gurry, Trans. AIME, 191(11), 1015-1018 (1951). 52Kit: J.A. Kitchener, J.O.M. Bockris, and D.A. Spratt, Trans. Faraday Soc., 48, 608-617 (1952). 53Coh: E.M. Cohn and L.J.E. Hofer, J. Chem. Phys., 21(2), 354-359 (1953). 56Pin: Z.G. Pinsker and S.V. Kaverin, Kristallografiya, 1(1), 66-72 (1956) in Russian; TR: Sov. Phys. Crystallogr., 1(1), 48-53 (1956). 57Pin: Z.G. Pinsker and S.V. Kaverin, Kristallografiya, 2, 386-392 (1957) in Russian; TR: Sov. Phys. Crystallogr., 2, 380-387 (1957). 58Ska: I.U. Skakov, I.N. Chernikova, and A.V. Sharshatkina, Dokl. Akad. Nauk SSSR, 118, 284-285 (1958) in Russian; TR: Sov. Phys. Dokl., 3, 151-153 (1958). 59Heu: T. Heumann and J. Grosse-Wordemann, Arch. EisenhЃttenwes., 30(1), 35-39 (1959) in German. 59Nag: S. Nagamura, J. Phys. Soc. Jpn., 14(2), 186-195 (1959). 59Smi: R.P. Smith, Trans. Metall. Soc. AIME, 215(12), 954-957 (1959). 60Buc: R.A. Buckley and W. Hume-Rothery, J. Iron Steel Inst., 196(12), 403-406 (1960). 61Ben: M.G. Benz and J.F. Elliott, Trans. Metall. Soc. AIME, 221(4), 323-331 ( 1961). 61Sch1: E. Scheil, T. Schmidt, and J. Wunning, Arch. EisenhЃttenwes., 32(4), 251-260 (1961) in German. 61Sch2: H. Schenck and G. Perbix, Arch. EisenhЃttenwes., 32(2), 123-127 (1961) in German. 63Hil: J.E. Hillard, Trans. Metall. Soc. AIME, 227(4), 429-438 (1963). 63Sen: J.P. Senateur and R. Fruchart, Compt. Rend., 256, 3114-3117 (1963) in French. 64Her: F.H. Herbstein and J.A. Snyman, Inorg. Chem., 3(6), 894-896 (1964). 64Ver: A.A. Vertman, V.K. Grigovich, N.A. Nedumov, and A.M. Samarin, Dokl. Akad. Nauk SSSR, 159(1), 121-124 (1964) in Russian; TR: Dokl. Chem. Proc. Acad. Sci. USSR, 159, 1131-1134 (1964). 66Hof: L.J.E. Hofer, U.S. Bureau Mines Bull. 631 (1966). 66Jac: K.H. Jack and S. Wild, Nature, 212, 248-250 (1966). 67Fil: E.S. Filippov, V.K. Grigorovich, and A.M. Samarin, Dokl. Akad. Nauk SSSR, 173(3), 564-566 (1967) in Russian. 68Dug: M.J. Duggin, Trans. Metall. Soc. AIME, 242(6), 1091-1100 (1968). 68Wad: T. Wada, Trans. Iron Steel Inst. Jpn., 8(1), 1-13 (1968). 69Ban: S. Ban-ya, J.F. Elliott, J. Chipman, Trans. Metall. Soc. AIME, 245(6), 1199-1206 (1969). 69Fru: R. Fruchart and A. Rouault, Ann. Chim., 4, 143-145 (1969) in French. 69Gri: V.K. Grigorovich, Izv. Akad. Nauk SSSR, Met., (1), 53-68 (1969) in Russian; TR: Russ. Metall., (1), 17-29 (1969). 72Hir: Y. Hirotsu and S. Nagakura, Acta Metall., 20(4), 645-655 (1972). 73Zhu1: A.A. Zhukov, L.E. Shterenberg, V.D. Kal'ner, V.A. Shalashov, N.A. Berezovskaya, V.K. Tomas, and R.L. Snezhnoi, Dokl. Akad. Nauk SSSR, 211(1), 145-157 (1973) in Russian; TR: Dokl. Chem. Proc. Acad. Sci. USSR, 211, 548-550 (1973). 73Zhu2: A.A. Zhukov, L.E. Shterenberg, V.A. Shalashov, V.K. Tomas, and N.A. Berezovskaya, Acta Metall., 21(3), 195-197 (1973). 73Zhu3: A.A. Zhukov, L.E. Shterenberg, V.A. Shalashov, V.K. Tomas, and N.A. Berezovskaya, Izv. Akad. Nauk SSSR, Met., (1), 181-184 (1973) in Russian; TR: Russ. Metall., (1), 127-130 (1973). 78Sch: I. Schmidt and E. Hornbogen, Z. Metallkd., 69(4), 221-227 (1978). 79Sch: E. Schurmann and R. Schmid, Arch. EisenhЃttenwes., 50(3), 101-106 (1979) in German. 79Wil: D.L. Williamson, K. Nakazawa, and G. Krauss, Metall. Trans. A, 10(9), 1351-1363 (1979). 81Tan: Y. Tanaka and K. Shimizu, Trans. Jpn. Inst. Met., 22(11), 779-788 (1981) . 82Chi: B. Chicco and W.R. Thorpe, Metall. Trans. A, 13(7), 1293-1297 (1982). 83Chi: B. Chicco and W.R. Thorpe, Metall. Trans. A, 14(2), 312-314 (1983). 83Kap: R. Kaplow, M. Ron, and N. DeCristofaro, Metall. Trans. A, 15(6), 1135- 1145 (1983). 84Oht: H. Ohtani, M. Hasebe, and T. Nishizawa, Trans. Iron Steel Inst. Jpn., 24, 857-864 (1984). 85Gus: P. Gustafson, Scand. J. Metall., 14, 259-267 (1985). 85Has: M. Hasebe, H. Ohtani, and T. Nishizawa, Metall. Trans. A, 16(5), 913- 921 (1985). 85Tak: M. Takahashi, K. Nushiro, and S. Ishio, Phys. Status Solidi (a), 89, K27-K29 (1985). Submitted to the APD Program. Complete evaluation contains 16 figures, 4 tables, and 246 references. Special Points of the Fe-C System