The Strain Dependence of Post-Deformation Softening during the Hot Compression of 304H Stainless Steel

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Experiments were carried out in which the dependence of the fractional softening on temperature, time and strain rate was determined in a 304H stainless steel. Three prestrain ranges were identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the DRX critical strain: strongly strain dependent softening by SRX alone with softening kinetics controlled by growth rate of the nuclei; 2) prestraining to above the DRX critical strain: SRX + MDRX softening with weaker strain dependence of the kinetics but still controlled by grain growth; 3) at a prestrain of ε* and beyond: nucleation-controlled MDRX softening with the full inhibition of SRX. The transition prestrain ε* can exceed the peak strain if the DRX grain refinement ratio g = D0/DDRX > 4. The transition to MDRX-dominated softening can be attributed to a constant value of the normalized strain hardening rate independent of the preloading temperature and strain rate. The softening data from the compression tests show that at ε*, the time for half softening t50 exhibits a minimum. These data differ somewhat from observations obtained in the torsion testing of solid bars, in which no strain dependence of t50 was detected at ε* and beyond. Whether or not the strain dependence of t50 vanishes in the MDRX range is sensitive to the test method employed to study the post-deformation softening.

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Materials Science Forum (Volumes 539-543)

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Edited by:

T. Chandra, K. Tsuzaki, M. Militzer , C. Ravindran

Pages:

100-107

Citation:

J. J. Jonas et al., "The Strain Dependence of Post-Deformation Softening during the Hot Compression of 304H Stainless Steel", Materials Science Forum, Vols. 539-543, pp. 100-107, 2007

Online since:

March 2007

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[1] C.M. Sellars: Mater. Sci. Technol., vol. 6, (1990), p.1072.

[2] G. Li, T.M. Maccagno, D.Q. Bai, and J.J. Jonas: ISIJ Int., vol. 36 (1996), p.1479.

[3] H.L. Andrade, M.G. Akben, and J.J. Jonas: Metall. Trans. A, vol. 14A (1983), p. (1967).

[4] S.H. Zahiri and P.D. Hodgson: Mater. Sci. Technol., vol. 20 (2004), No. 4, p.458.

[5] J.J. Jonas: Mat. Sci. Eng. A, vol. A184 (1994) , p.155.

[6] C. Roucoules and P.D. Hodgson: Mater. Sci. Technol., vol. 11 (1995), p.548.

[7] C. Roucoules, P.D. Hodgson, S. Yue, and J.J. Jonas: Metall. Mater. Trans. A, vol. 25A (1994), p.389.

[8] S.H. Cho, K.B. Kang and J.J. Jonas: ISIJ Int., vol. 41 (2001), p.766.

[9] S.H. Cho, K.B. Kang and J.J. Jonas: Mater. Sci. Technol., vol. 18 (2002), p.389.

[10] P.D. Hodgson: Mat. Sci. Technol., vol. 12 (1996), p.788.

[11] L.P. Karjalainen, T.M. Maccagno, and J.J. Jonas: ISIJ Int., vol. 35 (1995), p.1523.

[12] E.I. Poliak and J.J. Jonas: ISIJ Int., vol. 44, (2004) No. 11, p.1874.

[13] J. J. Jonas and E. I. Poliak: Mater. Sci. Forum, Vols. 426-432 (2003) p.57.

[14] E. I. Poliak and J.J. Jonas: Acta mater., vol. 44, (1996), No. 1, p.127.

[15] L.P. Karjalainen and J. Perttula: ISIJ Int., vol. 36 (1996), p.729.

[16] R.A.P. Djaic and J.J. Jonas: Metall. Trans., vol. 4, (1973), p.621.

[17] P. Uranga, A.I. Fernandez, B. Lopez, and J.M. Rodriguez-Ibabe: Mater. Sci. Eng. A, vol. A345 (2003), 319.

[18] S. H. Zahiri, S. M. Byon, S. -I. Kim, Y. Lee, and P.D. Hodgson: ISIJ Int., vol. 44, (2004), No. 11, p. (1918).

[19] M.R. Cartmill, M.R. Barnett, S.H. Zahiri, and P.D. Hodgson: ISIJ Int., vol. 45 (2005), No. 12, p.1224.

[20] A.I. Fernandez, B. Lopez, and J.M. Rodriguez-Ibabe: Mater. Sci. Forum, V. 467-470, (2004), p.1169.

[21] J.M. Rodriguez-Ibabe: Mater. Sci. Forum, Vols. 500-501, (2005), p.49.

[22] P.D. Hodgson, S.H. Zahiri, and J.J. Whale: ISIJ Int., vol. 44 (2004), p.1224.

[23] I. Weiss, T. Sakai, and J.J. Jonas: Metal Sci., vol. 18 (1984), p.77.

[24] T. Sakai and J.J. Jonas: Acta Metall., vol. 32 (1984), No. 2, p.189.

[25] F.J. Humphreys and M. Hatherly: Recrystallization and Related Annealing Phenomena, (Elsevier Science, Oxford, 1995) p.177, 188.

[26] Z. Xu and T. Sakai: Mater. Trans. JIM, vol. 32 (1991), No. 2, p.174.

[27] G.R. Stewart and A. M. Elwazri, private communication (2005) -40 -30 -20 -10 0 850 950 1050 1150 Temperature, oC Strain hardening rate θ*, MPa 0. 01/sec 0. 1/sec 0. 5/sec 1. 0/sec.

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