Metallurgical and Materials Transactions A

, Volume 50, Issue 2, pp 641–654 | Cite as

Creep Behavior and Microstructural Evolution of a Fe-20Cr-25Ni (Mass Percent) Austenitic Stainless Steel (Alloy 709) at Elevated Temperatures

  • Abdullah S. AlomariEmail author
  • N. Kumar
  • K. L. Murty


Understanding creep properties and microstructural evolution for candidate materials of the next-generation nuclear reactors is essential for design and safety considerations. In this work, creep tests were carried out at temperatures ranging from 973 to 1073 K and stresses 40 to 275 MPa followed by microstructural examinations of a Fe-20Cr-25Ni (mass pct) austenitic stainless steel (Alloy 709), a candidate structural material for the Sodium-cooled Fast Reactors. The apparent stress exponent and activation energy were found to be 6.8 ± 0.4 and 421 ± 38 kJ/mole, respectively. The higher activation energy relative to that of lattice self-diffusion together with the observation of dislocation-precipitate interactions in the crept specimens was rationalized based on the concept of threshold stress. The threshold stresses were estimated using a linear extrapolation method and found to decrease with increased temperature. By invoking the concept of threshold stresses, the true stress exponent and activation energy were found to be 4.9 ± 0.2 and 299 ± 15 kJ/mole, respectively. Together with the observation of subgrain boundary formation, the rate-controlling mechanism in the Alloy 709 was conclusively determined to be the high-temperature dislocation climb. Three types of precipitates were identified in the crept samples: Nb(C, N), Z-phases of sizes between 20 and 200 nm within the matrix and M23C6 with sizes between 200 and 700 nm within the matrix and on grain boundaries. Further, the analysis of creep rupture data at high stresses indicated that the Alloy 709 obeyed Monkman–Grant and modified Monkman–Grant relationships with creep damage tolerance factor of ~ 5. Using the Larson–Miller parameter, it was concluded that the Alloy 709 exhibited superior creep strengths relative to the other advanced austenitic steels.



The authors gratefully acknowledge the financial support from the Nuclear Energy University Programs (NEUP) of the Department of Energy, Office of Nuclear Energy for performing this research and Dr. Sam Sham of Argonne National Laboratory for various discussions and the experimental material. AA is thankful to KACST for funding his doctoral degree studies.


  1. 1.
    T.R. Allen, K. Sridharan, L. Tan, W.E. Windes, J.I. Cole, D.C. Crawford, G.S. Was: Nucl. Technol., 2008, vol. 162, pp. 342-357.CrossRefGoogle Scholar
  2. 2.
    K.L. Murty, I. Charit: J. Nucl. Mater., 2008, vol. 383, pp. 189-195.CrossRefGoogle Scholar
  3. 3.
    J.T. Busby: J. Nucl. Mater., 2009, vol. 392, pp. 301-306.CrossRefGoogle Scholar
  4. 4.
    S.L.Mannan, S.C.Chetal, B. Raj, S.B.Bhoje: Transactions- Indian Institute of Metals, 2003, vol. 56, pp. 1-35.Google Scholar
  5. 5.
    J.D. Cook, D.R. Harries, A.C. Roberts: in Creep Strength in Steels and High Temperature alloys, The Metals Society, London, 1972, p. 91.Google Scholar
  6. 6.
    W. Corwin: Fiscal Year (FY) 2015 Annual Planning Webinar, DOE, 2014.Google Scholar
  7. 7.
    T.-L. Sham, L. Tan, Y. Yamamoto: in Fast Reactors and Related Fuel Cycles: Safe Technologies and Sustainable Scenarios (FR13), IAEA, Vienna, 2015, pp. 1-9.Google Scholar
  8. 8.
    T. Takahashi, M. Sakakibara, M. Kikuchi, T. Ogawa, H. Sakurai, S. Araki, K. Nagao, and H. Yasuda: Nippon Steel Corporation, 1988.Google Scholar
  9. 9.
    H.E. Evans, D.A. Hilton: Nucl. Energy, 1973, vol. 18, pp. 33-38.Google Scholar
  10. 10.
    G. Knowles: Met. Sci., 1977, vol. 11, pp. 117-122.CrossRefGoogle Scholar
  11. 11.
    O.K. Chopra, K. Natesan: Metall. Trans. A, 1977, vol. 8, pp. 633-638.CrossRefGoogle Scholar
  12. 12.
    J.S. Zhang, P.E. Li, J.Z. Jin: Acta Metall. Mater., 1991, vol. 39, pp. 3063-3070.CrossRefGoogle Scholar
  13. 13.
    E. Evangelista, C. Guardamagna, L. Kloc, A. Rosen, S. Spigarelli: High Temp. Mater. Processes, 1995, vol. 14, pp. 151-161.Google Scholar
  14. 14.
    D.V.V. Satyanarayana, G. Malakondaiah, D.S. Sarma: Mater. Sci. Eng., A, 2002, vol. 323, pp. 119-128.CrossRefGoogle Scholar
  15. 15.
    L.J. Meng, J. Sun, H. Xing: J. Nucl. Mater., 2012, vol. 427, pp. 116-120.CrossRefGoogle Scholar
  16. 16.
    D.-B. Park, S.-M. Hong, K.-H. Lee, M.-Y. Huh, J.-Y. Suh, S.-C. Lee, W.-S. Jung: Mater. Charact., 2014, vol. 93, pp. 52-61.CrossRefGoogle Scholar
  17. 17.
    P. Ou, L. Li, X.-F. Xie, J. Sun: Acta Metall. Sin. 2015, 28, 1336–43.CrossRefGoogle Scholar
  18. 18.
    A.S. Alomari, N. Kumar, K.L. Murty: in Proceedings of the ASME 2017 Power and Engineering Conference, Charlotte, NC, USA, 2017.Google Scholar
  19. 19.
    J.K. Benz, L.J. Carroll, J.K. Wright, R.N. Wright, T.M. Lillo: Metall. Trans. A, 2014, vol. 45, pp. 3010-3022.CrossRefGoogle Scholar
  20. 20.
    T. Sourmail, H.K.D.H. Bhadeshia: Metall. Trans. A, 2005, vol. 36, pp. 23-34.CrossRefGoogle Scholar
  21. 21.
    B.K. Kim, L. Tan, C. Xu, Y. Yang, X. Zhang, M. Li: J. Nucl. Mater., 2016, vol. 470, pp. 229-235.CrossRefGoogle Scholar
  22. 22.
    C. Degueldre, J. Fahy, O. Kolosov, R.J. Wilbraham, M. Döbeli, N. Renevier, J. Ball, S. Ritter: J. Mater. Eng. Perform., 2018, vol. 27, pp. 2081-2088.CrossRefGoogle Scholar
  23. 23.
    T. Chen, L. Tan, Z. Lu, H. Xu: Acta Mater., 2017, vol. 138, pp. 83-91.CrossRefGoogle Scholar
  24. 24.
    D.S. Smith, N.J. Lybeck, J.K. Wright, R.N. Wright: Nucl. Eng. Des., 2017, vol. 322, pp. 331-335.CrossRefGoogle Scholar
  25. 25.
    A.S. Alomari, N. Kumar, K.L. Murty: Mater. Sci. Eng., A, 2018, vol. 729, pp. 157-160.CrossRefGoogle Scholar
  26. 26.
    A.S. Alomari, N. Kumar, K.L. Murty: in International Congress on Advances in Nuclear Power Plants (ICAPP), American Nuclear Society, Charlotte, NC, USA, 2018.Google Scholar
  27. 27.
    S. Upadhayay, H. Li, P. Bowen, A. Rabiei: Mater. Sci. Eng., A, 2018, vol. 733, pp. 338-349.CrossRefGoogle Scholar
  28. 28.
    K.L. Murty, F.A. Mohamed, J.E. Dorn: Acta Metall., 1972, vol. 20, pp. 1009-1018.CrossRefGoogle Scholar
  29. 29.
    T.G. Langdon: in Dislocations and properties of real materials, The Institute of Metals, London, 1985, pp. 221-238.Google Scholar
  30. 30.
    K.L. Murty, G. Dentel, J. Britt: Mater. Sci. Eng., A, 2005, vol. 410-411, pp. 28-31.CrossRefGoogle Scholar
  31. 31.
    J. Bird, A. Mukherjee, J. Dorn, in: Quantitative Relations between Properties and Microstructure, Israel Univ, 1969.Google Scholar
  32. 32.
    S. Latha, M.D. Mathew, P. Parameswaran, K. Sankara Rao, S.L. Mannan: Int. J. Press. Vessels Pip. 2008, 85, 866-870.CrossRefGoogle Scholar
  33. 33.
    S. Latha, M.D. Mathew, P. Parameswaran, K. Bhanu Sankara Rao, S.L. Mannan: Mater. Sci. Eng., A, 2010, vol. 527, pp. 5167-5174.CrossRefGoogle Scholar
  34. 34.
    A.F. Smith, G.B. Gibbs: Met. Sci. J., 1968, vol. 2, pp. 47-50.CrossRefGoogle Scholar
  35. 35.
    R. Lagneborg, B. Bergman: Met. Sci., 1976, vol. 10, pp. 20-28.CrossRefGoogle Scholar
  36. 36.
    R.S. Mishra, T.R. Bieler, A.K. Mukherjee: Acta Metall. Mater., 1995, vol. 43, pp. 877-891.CrossRefGoogle Scholar
  37. 37.
    T. Shrestha, M. Basirat, I. Charit, G.P. Potirniche, K.K. Rink, U. Sahaym: J. Nucl. Mater., 2012, vol. 423, pp. 110-119.CrossRefGoogle Scholar
  38. 38.
    A.F. Smith, G.B. Gibbs: Met. Sci. J., 1969, vol. 3, pp. 93-94.CrossRefGoogle Scholar
  39. 39.
    A.F. Smith: CEGB-RD/B/N–2330, Central Electricity Generating Board, United Kingdom, 1972.Google Scholar
  40. 40.
    A.F. Smith: Zeitschrift für Metallkunde, 1975, vol. 66, pp. 692-696.Google Scholar
  41. 41.
    S.L. Robinson, O.D. Sherby: Acta Metall., 1969, vol. 17, pp. 109-125.CrossRefGoogle Scholar
  42. 42.
    E.G. Wilson: in Creep strength in steel and high temperature alloys, The Metal Society, London, 1972, pp. 111-121.Google Scholar
  43. 43.
    J. Weertman: in Rate Processes in Plastic Deformation of Materials, ASM, Cleveland, Ohio, USA, 1972, pp. 315–336.Google Scholar
  44. 44.
    K.L. Murty: in Creep and fracture of engineering materials and structures, The Minerals, Metals & Materials Society, Irvine, USA, 1997, pp. 69-78.Google Scholar
  45. 45.
    S. Gollapudi, I. Charit, K.L. Murty: Acta Mater., 2008, vol. 56, pp. 2406-2419.CrossRefGoogle Scholar
  46. 46.
    B. Kombaiah, K.L. Murty: Metall. Trans. A, 2015, vol. 46, pp. 4646-4660.CrossRefGoogle Scholar
  47. 47.
    A. Horsewell: Metall. Trans. A, 1978, vol. 9, pp. 1843-1847.CrossRefGoogle Scholar
  48. 48.
    M.D. Mathew, G. Sasikala, K. Bhanu Sankara Rao, S.L. Mannan: Mater. Sci. Eng., A, 1991, vol. 148, pp. 253-260.CrossRefGoogle Scholar
  49. 49.
    N.D. Evans, P.J. Maziasz, J.P. Shingledecker, M.J. Pollard: Metall. Trans. A, 2010, vol. 41, pp. 3032-3041.CrossRefGoogle Scholar
  50. 50.
    B. Peng, H. Zhang, J. Hong, J. Gao, H. Zhang, J. Li, Q. Wang: Mater. Sci. Eng., A, 2010, vol. 527, pp. 4424-4430.CrossRefGoogle Scholar
  51. 51.
    V. Vodárek: Mater. Sci. Eng., A, 2011, vol. 528, pp. 4232-4238.CrossRefGoogle Scholar
  52. 52.
    Y. Zhou, Y. Li, Y. Liu, Q. Guo, C. Liu, L. Yu, C. Li, H. Li: J. Mater. Res., 2015, vol. 30, pp. 3642-3652.CrossRefGoogle Scholar
  53. 53.
    Z. Zhang, Z. Hu, H. Tu, S. Schmauder, G. Wu: Mater. Sci. Eng., A, 2017, vol. 681, pp. 74-84.CrossRefGoogle Scholar
  54. 54.
    H.J. Kestenbach, T. Luiz Da Silvelra, S.N. Monteiro: Metall. Trans. A, 1976, vol. 7, pp. 155-158.CrossRefGoogle Scholar
  55. 55.
    E.C.Monkman, N.J.Grant: Proc. Am. Soc. Test. Mater., 1956, vol. 56, pp. 593.Google Scholar
  56. 56.
    F. Dobeš, K. Milička: Met. Sci., 1976, vol. 10, pp. 382-384.CrossRefGoogle Scholar
  57. 57.
    M.F. Ashby, B.F. Dyson: in Advances in Fracture Research, Pergamon Press, Oxford, 1984, pp. 3–30.Google Scholar
  58. 58.
    B. Wilshire, H. Burt: Int. J. Press. Vessels Pip., 2008, vol. 85, pp. 47-54.CrossRefGoogle Scholar
  59. 59.
    European Technology Development, 2005.Google Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2018

Authors and Affiliations

  • Abdullah S. Alomari
    • 1
    • 2
    Email author
  • N. Kumar
    • 1
    • 3
  • K. L. Murty
    • 1
  1. 1.Department of Nuclear EngineeringNorth Carolina State UniversityRaleighUSA
  2. 2.Atomic Energy Research InstituteKing Abdulaziz City for Science and TechnologyRiyadhSaudi Arabia
  3. 3.Metallurgical and Materials EngineeringThe University of AlabamaTuscaloosaUSA

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