Abstract
The effect of microstructural evolution on superplastic deformation parameters, such as the nature of σ-ε plots, strain-rate sensitivity parameter, and activation energy, were studied for unstable and thermally stable microstructures of a Zr-2.5 wt pct Nb pressure-tube alloy. Two types of differential strain-rate tests (increasing temperature (IT) and decreasing temperature (DT), in the temperature range of 610 °C to 810 °C at 20 °C intervals) were conducted within a strain-rate range of 10−5 to 10−3 s−1. Single specimens were used to obtain the σ-ε plots for all the test temperatures in the aforementioned temperature range. The effect of orientation (with respect to the axial direction of the tube) on the superplastic deformation parameters was also studied. The microstructural evolution was studied along the three orthogonal planes of the tube by water quenching underformed samples in the beginning of differential strain-rate tests at each test temperature. The observed apparent activation-energy values associated with deformation were in the two distinct ranges of 287 to 326 and 151 to 211 kJ/mole. In the temperature range of 730 °C to 810 °C, the apparent activation-energy value depended on the direction of approach of the test temperature. The mechanisms of superplastic deformation in this alloy were found to be dislocation climb—controlled creep in region III and grain-boundary sliding accommodated by grain-boundary diffusion or lattice diffusion in the α or β phases in region II. Based on the observed microstructural features, a model to explain the σ-ε plots and apparent activation energy has been proposed.
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C.D. Williams: Reactor Technol., 1970, vol. 13 (2), pp. 147–69.
E.F. Ibrahim and B.A. Cheadle: Can. Metall. Q., 1985, vol. 24 (3), pp. 273–81.
R.G. Fleck, V. Perovic, and E.T.C. Ho: Ontario Hydro Res. Rev., 1993, No. 8, pp. 1–14.
B.A. Cheadle, C.E. Coleman, and H. Litcht: Nucl. Technol., 1982, vol. 57, pp. 413–25.
G.L. Miller: Zirconium, Butterworth Scientific Pub., London, 1957, pp. 186–205.
R.S. Ambartsumyan, A.A. Kiselev, R.V. Grebenmkov, V.A. Myshkin, L.S. Tsuprun, and A.F. Nikulina: 2nd United Nations Conf., Geneva, 1958, vol. 5, p. 12.
N.R. McDonald: J. Aust. Inst. Met., 1971, vol. 16 (4), pp. 179–94.
D.L. Douglass: The Metallurgy of Zirconium, Atomic Energy Review, International Atomic Energy Agency, Vienna, 1971, pp. 1–466.
R. Krishnan and M.K. Asundi: Proc. Ind. Acad. Sci. (Eng. Sci.), 1981, vol. 4, pp. 41–50.
“Kakrapar Atomic Power Station Safety Report: Accident Analysis Rev. 1,” 1996, Nuclear Power Corportion, A Government of India Enterprise, Bombay-94, vol. II, pp. 5.17–5.60.
N.A. Makhutov, L.P. Fedorovich, A.V. Chirkin, B.G. Parfenov, and A.I. Tananov: Metallovedenie-i-Termicheskaya-Obrabotka-Metallov-USSR, 1982, No. 7, pp. 37–40.
H.E. Rosinger and A.E. Unger: Report No. 6418 (AECL 6418), Dec. 1979, Atomic Energy of Canada Limited, Chalk River Nuclear Laboratories, Chalk River, Ontario, Canada, pp. 1–36.
K. Nuttall: Scripta Metall., 1976, vol. 10 (9), pp. 835–40.
R.N. Singh, R. Kishore, T.K. Sinha, and B.P. Kashyap: Scripta Metall. Mater., 1993, vol. 28 (8), pp. 937–42.
R.S.W. Shewfelt: Can. Metall. Q., 1984, vol. 23, pp. 441–45.
R.N. Singh, R. Kishore, T.K. Sinha, and B.P. Kashyap: Materials Science Forum, Proc. Int. Conf. on Superplasticity in Advanced Materials 1997, Bangalore, India, Jan. 29–31, 1977, Atul H. Chokshi, ed., Trans Tech Publications, Aedermannsdorf, Switzerland, 1997, vols. 243–45. pp. 499–504.
D. Srivastava, G.K. Dey, and S. Banerjee: Metall. Trans. A, 1995, vol. 26A, pp. 2707–18.
Binary Alloy Phase Diagram, 2nd ed., T.B. Massalski, ed., ASM INTERNATIONAL, 1992, vol. 3, pp. 2788–89.
T.H. Courtney: Mechanical Behaviour of Materials, International ed., McGraw-Hill Book Co., Singapore, 1990, pp. 302–09.
S.V. Shukla, C. Chandrashekhrayya, R.N. Singh, R. Fotedar, R. Kishore, T.K. Sinha, and B.P. Kashyap: J. Nucl. Mater., 1999, vol. 273, pp. 130–38.
M.G. Zelin and A.K. Mukherjee: Mater. Sci. Eng. A, 1996, vol. 208, pp. 210–25.
K. Matsuki, H. Morita, M. Yamada, and Y. Murakami: Met. Sci., 1977, vol. 11, pp. 156–63.
T.L. Spingarn and W.D. Nix: Acta Metall., 1978, vol. 26, pp. 1389–98.
R.C. Gifkins: Metall. Trans. A, 1976, vol. 7A, pp. 1225–32.
M. Surrey and B. Baudlet: Res. Mechanica, 1981, vol. 2, pp. 163–73.
George E. Dieter: Mechanical Metallurgy, SI Metric ed., McGraw-Hill Book Co. New York, NY, 1988, pp. 127–30.
N.E. Paton and C.H. Hamilton: Metall. Trans. A, 1979, vol. 10A, pp. 241–50.
A.M. Garde, H.M. Chung, and T.F. Kassner: Acta Metall., 1978, vol. 26 (1), pp. 153–66.
K.L. Murty, B.V. Tanikella, and J.C. Earthman: Acta Metall. Mater., 1994, vol. 42 (11), pp. 3653–61.
Richard W. Hertzberg: Deformation and Fracture Mechanics of Engineering Materials, 2nd ed., John Wiley & Sons, New York, NY, 1983, pp. 154–58.
M.J. Iribarren and F. Dyment: J. Nucl. Mater., 1989, vol. 161, pp. 148–52.
R. Piotrkowski: J. Nucl. Mater., 1991, vol. 183, pp. 221–25.
J.J. Kearns, J.E. McCauley, and F.A. Nichols: J. Nucl. Mater., 1976, vol. 61, pp. 169–84.
B.P. Kashyap, R. Pathak, K. Narasimhan, R. Kishore, R.K. Fotedar, and T.K. Sinha: J. Mater. Sci., 1999, vol. 34, pp. 645–51.
L. Briottet, J.J. Jonas, and E. Montheillet: Acta Metall., 1996, vol. 44, pp. 1665–72.
Binary Alloy Phase Diagram, 2nd ed. T.B. Massalski, ed., ASM INTERNATIONAL, Metal Parks, OH, 1992, pp. 2940–41.
K. Duong and F.A. Mohamed: Acta Mater., 1998, vol. 46 (13), pp. 4571–86.
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Singh, R.N., Kishore, R., Sinha, T.K. et al. Microstructural instability and superplasticity in a Zr-2.5 Wt Pct Nb pressure-tube alloy. Metall Mater Trans A 32, 2827–2840 (2001). https://doi.org/10.1007/s11661-001-1033-6
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DOI: https://doi.org/10.1007/s11661-001-1033-6