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Nucleation sites for ultrafine ferrite produced by deformation of austenite during single-pass strip rolling

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Abstract

An austenitic Ni-30 wt pct Fe alloy, with a stacking-fault energy and deformation characteristics similar to those of austenitic low-carbon steel at elevated temperatures, has been used to examine the defect substructure within austenite deformed by single-pass strip rolling and to identify those features most likely to provide sites for intragranular nucleation of ultrafine ferrite in steels. Samples of this alloy and a 0.095 wt pct C-1.58Mn-0.22Si-0.27Mo steel have been hot rolled and cooled under similar conditions, and the resulting microstructures were compared using transmission electron microscopy (TEM), electron diffraction, and X-ray diffraction. Following a single rolling pass of ∼40 pct reduction of a 2mm strip at 800 °C, three microstructural zones were identified throughout its thickness. The surface zone (of 0.1 to 0.4 mm in depth) within the steel comprised a uniform microstructure of ultrafine ferrite, while the equivalent zone of a Ni-30Fe alloy contained a network of dislocation cells, with an average diameter of 0.5 to 1.0 µm. The scale and distribution and, thus, nucleation density of the ferrite grains formed in the steel were consistent with the formation of individual ferrite nuclei on cell boundaries within the austenite. In the transition zone, 0.3 to 0.5 mm below the surface of the steel strip, discrete polygonal ferrite grains were observed to form in parallel, and closely spaced “rafts” traversing individual grains of austenite. Based on observations of the equivalent zone of the rolled Ni-30Fe alloy, the ferrite distribution could be correlated with planar defects in the form of intragranular microshear bands formed within the deformed austenite during rolling. Within the central zone of the steel strip, a bainitic microstructure, typical of that observed after conventional hot rolling of this steel, was observed following air cooling. In this region of the rolled Ni-30Fe alloy, a network of microbands was observed, typical of material deformed under plane-strain conditions.

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References

  1. R. Priestner and E. de los Rios: Met. Technol., 1980, pp. 309–16.

  2. P.D. Hodgson, M.R. Hickson, and R.K. Gibbs: Mater. Sci. Forum, 1998, vols. 284–286, pp. 63–73.

    Google Scholar 

  3. X.J. Zhang, P.D. Hodgson, and P.F. Thomson: J. Mater. Processing Technol., 1996, vol. 60, pp. 615–620.

    Article  Google Scholar 

  4. P.J. Hurley and P.D. Hodgson: Mater. Sci. Eng. A, 2001, vol. 302, issue 2, pp. 206–14.

    Article  Google Scholar 

  5. P.J. Hurley, B.C. Muddle, P.D. Hodgson, C.H.J. Davies, B.P. Wynne, P. Cizek, and M.R. Hickson: Mater. Sci. Forum, 1998, vols. 284–286, pp. 159–66.

    Article  Google Scholar 

  6. P. Cizek, D.G. McCulloch, and B.A. Parker: Proc. 13th Biennial Conf. of the Australian Society of Electron Microscopy—ACEM-13, Gold Coast, Australia, D. Allen, J. Barry, T. Bostrom, L.M. Hogan, and M.S. Pennisi, eds., The Australian Society of Electron Microscopy, Sydney, Australia, 7–11 February, 1994, p. 110.

    Google Scholar 

  7. B.D. Cullity, Elements of X-ray Diffraction, 2nd ed., Addison-Wesley Publishing Company, Reading, MA, 1978, p. 308.

    Google Scholar 

  8. H. Bunge: Texture Analysis in Materials Science: Mathematical Methods, 1st ed. Butterworth and Co., Berlin, 1982, pp. 1–41.

    Google Scholar 

  9. J.S. Kallend, U.F. Kocks, A.D. Rollett, and H.-R. Wenk: Mater. Sci. Eng. A, 1991, vol. A132, pp. 1–11.

    Google Scholar 

  10. M. Holscher, D. Raabe, and K. Lucke: Acta Metall. Mater., 1994, vol. 42 (3), pp. 879–86.

    Article  Google Scholar 

  11. D. Raabe: J. Mater. Sci., 1995, vol. 30, pp. 47–52.

    Article  CAS  Google Scholar 

  12. A. Korbel, J.D. Embury, M. Hatherly, P.L. Martin, and H.W. Erbsloh: Acta Metall. Mater., 1986, vol. 34 (10), pp. 1999–2009.

    Article  CAS  Google Scholar 

  13. C. Donadille, R. Valle, P. Dervin, and R. Penelle: Acta Metall. Mater., 1989, vol. 37 (6), pp. 1547–71.

    Article  CAS  Google Scholar 

  14. B. Bay, N. Hansen, D.A. Hughes, and D. Kuhlmann-Wilsdorf: Acta Metall. Mater., 1992, vol. 40 (2), pp. 205–19.

    Article  CAS  Google Scholar 

  15. P. Cizek: Monash University, Melbourne, unpublished research, 1998.

  16. R. Kaspar, J.S. Disti, and O. Pawelski: Steel Res., 1988, vol. 59 (9), pp. 421–25.

    CAS  Google Scholar 

  17. F.H. Samuel, S. Yue, J.J. Jonas, and K.R. Barnes: Iron Steel Inst. Jpn. Int., 1990, vol. 30 (3), pp. 216–25.

    CAS  Google Scholar 

  18. P.J. Hurley, P.D. Hodgson, and B.C. Muddle: Scripta Mater., 1999, vol. 40 (4), pp. 433–38.

    Article  CAS  Google Scholar 

  19. P.J. Hurley: Ph.D. Thesis, Monash University, Melbourne, 1999.

    Google Scholar 

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Hurley, P.J., Muddle, B.C. & Hodgson, P.D. Nucleation sites for ultrafine ferrite produced by deformation of austenite during single-pass strip rolling. Metall Mater Trans A 32, 1507–1517 (2001). https://doi.org/10.1007/s11661-001-0238-z

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