Abstract
A composite microstructure consisting of upper bainite laths and lower bainite plates, both carbide-free, plate (twinned) martensite, and carbon-enriched retained austenite, was produced by air-cooling a medium-carbon alloy steel (0.55 pct C, 1.35 pct Si, 0.78 pct Mn, 0.45 pct Mo) from 900 °C. Well-defined midribs and subunits were found to be associated with both the upper bainite laths and lower bainite plates, clearly showing that the two kinds of bainite growvia a sympathetic nucleation and growth process. The orientation relationship between the bainite and austenite, as determined by electron diffraction, showed that the close-packed planes in the two phases were separated by 0.5 deg and the close-packed directions were 1.9 apart. The habit plane determined from the midrib was (5 127)f, about 20 deg away from the nearly parallel close-packed planes (111)f/(011)b. The experimentally determined orientation relation-ship and habit plane (as defined by the midrib) were in good agreement with the predictions of the phenomenological theory of martensite crystallography.
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H.K.D.H. Bhadeshia and J.W. Christian:Metall. Trans. A, 1990, vol. 21A, pp. 767–97.
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, T. Furuhara, J.M. Rigsbee, W.T. Reynolds, Jr., and J.M. Howe:Metall. Trans. A, 1990, vol. 21A, pp. 2369–2409.
G.R. Srinivasan and C.M. Wayman:Acta Metall., 1968, vol. 16, pp. 621–36.
H.K.D.H. Bhadeshia and D.V. Edmonds:Acta Metall., 1980, vol. 28, pp. 1265–73.
Y. Ohomori:Trans. Iron Steel Inst. Jpn., 1971, vol. 11, pp. 95–101.
S. Hoekstra:Acta Metall., 1980, vol. 26, pp. 507–17.
B.P.J. Sandvik:Metall. Trans. A, 1982, vol. 13A, pp. 777–87.
C. Servant and G. Cizeron:Acta Metall., 1989, vol. 37, pp. 465–76.
C.P. Luo and Z.Y. Liu:Prog. Mater. Sci., 1990, vol. 4, pp. 200–04 (in Chinese).
J.F. Breedis and C.M. Wayman:Trans. AIME, 1962, vol. 224, pp. 1128–33.
R.L. Patterson and C.M. Wayman:Acta Metall., 1966, vol 14 pp. 347–69.
C.P. Luo and G.C. Weatherly:Acta Metall., 1987, vol. 35, pp. 1963–72.
H.K.D.H. Bhadeshia and D.V. Edmonds:Metall. Trans. A, 1979, vol. 10A, pp. 895–907.
R.F. Hehemann:Phase Transformations, ASM, Metals Park OH 1970, p. 397.
G. Spanos, H.S. Fang, and H.I. Aaronson:Metall. Trans. A, 1990, vol. 21A, pp. 1381–90.
A.K. Head, P. Humble, L.M. Clareborough, A.J. Morton, and C.T. Forwood:Defects in Crystalline Solids, North-Holland, Amsterdam, 1973, vol. 7.
M.S. Wechsler, D.S. Liebermann, and T.A. Read:Trans. AIME, 1953, vol. 197, pp. 1503–15.
M.S. Wechsler, D.S. Liebermann, and T.A. Read:Trans. AIME 1960, vol. 218, pp. 202–07.
C.M. Wayman:Introduction to the Crystallography of Martensite Transformations, Macmillan, New York, NY, 1964.
H. Okamoto and M. Oka:Metall. Trans A 1986 vol 17A pp. 1113–20.
U. Dahmen:Acta Metall., 1982, vol. 30, pp. 63–73.
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Luo, C.P., Weatherly, G.C. & Liu, ZY. The crystallography of bainite in a medium-carbon steel containing Si, Mn, and Mo. Metall Trans A 23, 1403–1411 (1992). https://doi.org/10.1007/BF02647323
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DOI: https://doi.org/10.1007/BF02647323