Abstract
A scanning transmission electron microscope (STEM) technique was used to measure Mo concentrations at ferrite:austenite (α:γ) interfaces in an Fe-0.24 pct C-0.93 pct Mo alloy partially transformed at 650°C, 630°C, and 610°C. These concentrations were quite small at 650°C, which is just below the bay temperature of the time-temperature-transformation (TTT) curve for the initiation of ferrite formation. There were larger concentrations at 630°C, a temperature at which transformation stasis (incomplete transformation) occurred. Concentrations at 610°C were intermediate between the values observed at 650°C and 630°C. The average accumulation at the latter temperatures increased appreciably as a function of transformation time. After each heat treatment, there was considerable variation in Mo accumulation from one α:γ interface to another and, to a lesser extent, from one region to another along the same interface. These higher Mo concentrations were deduced to have developed largely through volume diffusion of Mo, mainly through ferrite, to interfaces whose ledgewise growth had been interrupted by growth stasis. (Mo2C precipitation at α:γ boundaries occurred only at the end of growth stasis.) It appears that only a very small amount of Mo segregation is needed, probably at specific interfacial sites, in order to produce growth cessation. Growth kinetics anomalies of this kind continue to provide the best evidence available for the operation of a coupled-solute drag effect.
Similar content being viewed by others
References
P.G. Boswell, K.R. Kinsman, G.J. Shiflet, and H.I. Aaronson: Mechanical Properties and Phase Transformations in Engineering Materials, TMS, Warrendale, PA, 1986, pp. 445–66.
H.I. Aaronson, H.A. Fletcher, G.D.W. Smith, A.J. Garratt-Reed, W.T. Reynolds, Jr., and G.R. Purdy: Steel Heat Treating in the New Millennium, ASM, Materials Park, OH, 2000, pp. 620–30.
H.I. Aaronson, W.T. Reynolds, Jr., G.J. Shiflet, and G. Spanos: Metall. Trans. A, 1990, vol. 21A, pp. 1343–80.
H.I. Aaronson, G. Spanos, and W.T. Reynolds, Jr.: Scripta Mater., 2002, vol. 47, pp. 139–44.
F. Wever and E. Lange: Mitt. K.-W. Inst. Eisenforschung, 1932, vol. 14, pp. 71–83.
R.F. Hehemann, K.R. Kinsman, and H.I. Aaronson: Metall. Trans., 1972, vol. 3, pp. 1077–94.
M. Enomoto and H.I. Aaronson: Metall. Trans. A, 1986, vol. 17A, pp. 1385–97.
G.J. Shiflet and H.I. Aaronson: Metall. Trans. A, 1990, vol. 21A, pp. 1413–32.
T. Lyman and A.R. Troiano: Trans. ASM, 1946, vol. 37, pp. 402–48.
R.W.K. Honeycombe: Metall. Trans. A, 1975, vol. 7A, pp. 915–36.
H. Tsubakino and H.I. Aaronson: Metall. Trans. A, 1987, vol. 18A, pp. 2047–59.
H.A. Fletcher, A.J. Garratt-Reed, H.I. Aaronson, G.R. Purdy, W.T. Reynolds, Jr., and G.D.W. Smith: Scripta Mater., 2001, vol. 45, pp. 561–67.
K.R. Kinsman and H.I. Aaronson: Transformation and Hardenability in Steels, Climax Molybdenum Co., Ann Arbor, MI, 1967, pp. 39–53.
J.R. Bradley and H.I. Aaronson: Metall. Trans. A, 1981, vol. 12A, pp. 1729–41.
G.R. Purdy and Y.M. Brechet: Acta Mater., 1995, vol. 43, pp. 3763–74.
J.W. Cahn: Acta Metall., 1962, vol. 10, pp. 789–98.
M. Enomoto: Acta Mater., 1999, vol. 47, pp. 3533–40.
I. Stark and G.D.W. Smith: Phase Transformations ’87, Cambridge, United Kingdom, 1987, Institute of Metals, London, 1987, pp. 475–81.
W.T. Reynolds, Jr., S.S. Brenner, and H.I. Aaronson: Scripta Metall., 1988, vol. 22, pp. 1343–48.
E.S.K. Menon, W.T. Reynolds, Jr., and A.G. Fox: Microscopy and Microanalysis, Springer, New York, NY, 1997, vol. 3, suppl. 2, pp. 553–54
W.T. Reynolds, Jr., F.Z. Li, C.K. Shui, and H.I. Aaronson: Metall. Trans. A, 1990, vol. 21A, pp. 1433–63.
M. Enomoto, N. Maruyama, K.M. Wu, and T. Tarui: Mater. Sci. Eng. A, 2003, vol. A343, pp. 151–57.
C.K. Shui, W.T. Reynolds, Jr., G.J. Shiflet, and H.I. Aaronson: Metallography, 1988, vol. 21, pp. 91–102.
J.A.S. Ikeda, Y.-M. Chiang, and C.G. Madras: Ceram. Trans., 1991, vol. 24, pp. 341–48.
A.J. Garratt-Reed, G. Cliff, G.W. Lorimer, and R. Pilkington: MRS Symp. Proc., 1997, vol. 458, pp. 103–08.
A.J. Garratt-Reed: Proc. 50th Ann. Mtg. EMSA, San Francisco, CA, 1992, San Francisco Press, San Francisco, CA, 1992, pp. 1206–07.
K.M. Wu, M. Kagayama, and M. Enomoto: Mater. Sci. Eng. A, 2002, vol. A343, pp. 143–50.
H.I. Aaronson, W.T. Reynolds, Jr., and G.R. Purdy: Metall. Mater. Trans. A, 2004, vol. 35A, pp. 1187–1210.
K.M. Wu and M. Enomoto: Scripta Mater., 2002, vol. 46, pp. 569–74.
R.E. Hackenberg, D.P. Nordstrom, and G.J. Shiflet: Scripta Mater., 2002, vol. 47, pp. 357–61.
J.R. Bradley, J.M. Rigsbee, and H.I. Aaronson: Metall. Trans. A, 1977, vol. 8A, pp. 323–33.
K.R. Kinsman and H.I. Aaronson: Metall. Trans., 1973, vol. 4, pp. 959–67.
K. Oi, C. Lux, and G.R. Purdy: Acta Mater., 2000, vol. 48, pp. 2147–55.
H.I. Aaronson, H.A. Domain, and G.M. Pound: Trans. TMS-AIME, 1966, vol. 236, pp. 768–81.
J.W. Cahn: Acta Metall., 1956, vol. 4, pp. 449–59.
T. Obara, W.F. Lange III, H.I. Aaronson, and B.E. Dom: Proc. Int. Conf on Solid → Solid Phase Transformations, TMS-AIME, Warrendale, PA, 1983, pp. 1105–09.
W.F. Lange III, M. Enomoto, and H.I. Aaronson: Metal. Trans. A, 1988, vol. 19A, pp. 427–40.
H.I. Aaronson and K.C. Russell: Proc. Int. Conf. on Solid → Solid Phase Transformations, TMS-AIME, Warrendale, PA, 1982, pp. 371–97.
Tadashi Furuhara and Tadashi Maki: Mater. Trans. JIM, 1992, vol. 33, pp. 734–39.
T. Furuhara and H.I. Aaronson: Acta Metal. Mater., 1991, vol. 39, pp. 2887–99.
T. Furuhara, J.M. Howe, and H.I. Aaronson: Acta Metal. Mater., 1991, vol. 39, pp. 2873–86.
J.M. Howe, U. Dahmen, and R. Gronsky: Phil. Mag. A, 1987, vol. 56, pp. 31–51.
H.I. Aaronson: Metall. Trans. A, 1993, vol. 24A, p. 241.
J.M. Howe and N. Prahbu: Acta Metall., 1990, vol. 38, pp. 881–87.
N. Prabhu and J.M. Howe: Acta Metall., 1990, vol. 38, pp. 889–96.
C. Laird and H.I. Aaronson: Acta Metall., 1969, vol. 17, pp. 505–19.
K.R. Kinsman, E. Eichen, and H.I. Aaronson: Metall. Trans. A., 1975, vol. 6A, pp. 303–17.
G.R. Purdy, W.T. Reynolds, Jr., and H.I. Aaronson: Proc. Int. Conf. on Solid → Solid Phase Transformations ’99, M. Koiwa, K. Otsuka, and T. Miyazaki, eds., Japan Institute of Metals, Sendai, Japan, 1999, pp. 1461–64.
H.I. Aaronson: The Mechanism of Phase Transformations in Crystalline Solids, Institute of Metals, London, 1969, pp. 270–81.
M. Hillert: The Mechanism of Phase Transformations in Crystalline Solids, Institute of Metals, London, 1969, pp. 231–47.
H. Goldenstein and H.I. Aaronson: Metall. Trans. A, 1990, vol. 21A, pp. 1465–78.
Hong-Sheng Fang, Jia-Jun Wang, and Yan-Kang Zheng: Metall. Mater. Trans. A, 1994, vol. 25A, pp. 2001–07.
J.M. Rigsbee and H.I. Aaronson: Acta Metall., 1979, vol. 27, pp. 365–76.
J.M. Rigsbee and H.I. Aaronson: Acta Metall., 1979, vol. 27, pp. 351–63.
J. Fridberg, L.-E. Torndahl, and M. Hillert: Jernkont. Ann., 1969, vol. 153, pp. 263–76.
Dimitri Malakhov: McMaster University, Hamilton, ON, Canada, private communication, 2003.
W.T. Reynolds, Jr. and K. Hono: National Institute for Materials Science, Tsukuba, Japan, unpublished research, 1997.
H. Guo, H.I. Aaronson, M. Enomoto, and G.R. Purdy: McMaster University, Hamilton, ON, Canada, unpublished research, 2003.
A. Cerezo, D.J. Larson, and G.D.W. Smith: MRS Bull., 2001, vol. 26, pp. 102–07.
Author information
Authors and Affiliations
Additional information
This article is based on a presentation given in the symposium “The Effect of Alloying Elements on the Gamma to Alpha Transformation in Steels,” October 6, 2002, at the TMS Fall Meeting in Columbus, Ohio, under the auspices of the McMaster Centre for Steel Research and the ASM-TMS Phase Transformations Committee.
Rights and permissions
About this article
Cite this article
Humphreys, E.S., Fletcher, H.A., Hutchins, J.D. et al. Molybdenum accumulation at ferrite: Austenite interfaces during isothermal transformation of an Fe-0.24 pct C-0.93 pct Mo alloy. Metall Mater Trans A 35, 1223–1235 (2004). https://doi.org/10.1007/s11661-004-0296-0
Issue Date:
DOI: https://doi.org/10.1007/s11661-004-0296-0