Metallurgical and Materials Transactions A

, Volume 40, Issue 8, pp 1868–1880 | Cite as

Effect of Alloying Additions on Phase Equilibria and Creep Resistance of Alumina-Forming Austenitic Stainless Steels

  • Y. Yamamoto
  • M.L. Santella
  • M.P. Brady
  • H. Bei
  • P.J. Maziasz


The high-temperature creep properties of a series of alumina-forming austenitic (AFA) stainless steels based on Fe-20Ni-(12-14)Cr-(2.5-4)Al-(0.2-3.3)Nb-0.1C (weight percent) were studied. Computational thermodynamics were used to aid in the interpretation of data on microstructural stability, phase equilibria, and creep resistance. Phases of MC (M: mainly Nb), M23C6 (M: mainly Cr), B2 [β-(Ni,Fe)Al], and Laves [Fe2(Mo,Nb)] were observed after creep-rupture testing at 750 °C and 170 MPa; this was generally consistent with the thermodynamic calculations. The creep resistance increased with increasing Nb additions up to 1 wt pct in the 2.5 and 3 Al wt pct alloy series, due to the stabilization of nanoscale MC particles relative to M23C6. Additions of Nb greater than 1 wt pct decreased creep resistance in the alloy series due to stabilization of the Laves phase and increased amounts of undissolved, coarse MC, which effectively reduced the precipitation of nanoscale MC particles. The additions of Al also increased the creep resistance moderately due to the increase in the volume fraction of B2 phase precipitates. Calculations suggested that optimum creep resistance would be achieved at approximately 1.5 wt pct Nb in the 4 wt pct Al alloy series.


Creep Resistance Lave Phase Solution Heat Treatment Sigma Phase Formation Scanning Electron Microscope Backscatter Electron Image 
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The authors thank E.P. George, C.T. Liu, and J.H. Schneibel for helpful comments on this manuscript. This work was funded by the United States Department of Energy (USDOE) Fossil Energy Advanced Research Materials program. The Oak Ridge National Laboratory is managed by UT–Battelle, LLC (Oak Ridge, TN), for the USDOE under Contract No. DE-AC05-00OR22725. The authors also acknowledge the SHaRE User Facility at the Oak Ridge National Laboratory, sponsored by the USDOE Office of Basic Energy Sciences, Division of Scientific User Facilities.


  1. 1.
    R. Viswanathan and W. Bakker: J. Mater. Eng. Perf., 2001, vol. 10, pp. 81–95.CrossRefGoogle Scholar
  2. 2.
    R. Viswanathan and W. Bakker: J. Mater. Eng. Perf., 2001, vol. 10, pp. 96–101.CrossRefGoogle Scholar
  3. 3.
    P. Kofstad: High Temperature Corrosion, Elsevier, London, 1988, pp. 389–534.Google Scholar
  4. 4.
    E.J. Opila: Mater. Sci. Forum, 2004, vols. 461–464, pp. 765–74.CrossRefGoogle Scholar
  5. 5.
    B.A. Pint, R. Peraldi, and P.J. Maziasz: Mater. Sci. Forum, 2004, vols. 461–464, pp. 815–22.CrossRefGoogle Scholar
  6. 6.
    P.J. Maziasz, R.W. Swindeman, J.P. Shingledecker, K.L. More, B.A. Pint, E. Lara-Curzio, and N.D. Evans: Proc. 6th Int. Charles Parsons Turbine Conf., A. Strang, R.D. Conroy, W.M. Banks, M. Blackler, J. Leggett, G.M. McColvin, S. Simpson, M. Smith, F. Starr, and R.W. Vanstone, eds., The Institute of Materials, Minerals, and Mining, Maney Publishing, London, 2003, pp. 1057–73.Google Scholar
  7. 7.
    Y. Yamamoto, M.P. Brady, Z.P. Lu, P.J. Maziasz, C.T. Liu, B.A. Pint, K.L. More, H.M. Meyer, and E.A. Payzant: Science, 2007, vol. 316 (5823), pp. 433–36.PubMedCrossRefADSGoogle Scholar
  8. 8.
    M.P. Brady, Y. Yamamoto, Z.P. Lu, P.J. Maziasz, C.T. Liu, B.A. Pint, and M.L. Santella: Stainless Steel World Mag., Mar. 2008, vol. 20, pp. 23–29.Google Scholar
  9. 9.
    M.P. Brady, Y. Yamamoto, M.L. Santella, and B.A. Pint: Scripta Mater. 2007, vol. 57 (12), pp. 1117–20.CrossRefGoogle Scholar
  10. 10.
    M.P. Brady, Y. Yamamoto, M.L. Santella, P.J. Maziasz, B.A. Pint, and C.T. Liu: JOM, vol. 60 (7), 2008, pp. 12–18.CrossRefGoogle Scholar
  11. 11.
    M.P. Brady, Y. Yamamoto, B.A. Pint, M.L. Santella, P.J. Maziasz, and L.R. Walker: Mater. Sci. Forum, 2008, vols. 595–598, pp. 725–32.CrossRefGoogle Scholar
  12. 12.
    Y. Yamamoto, M.P. Brady, M.L. Santella, B.A. Pint, and P.J. Maziasz: Proc. 33rd Int. Tech. Conf. Coal Utilization, Fuel Systems, B.A. Sakkestad, ed., Coal Technology Association, Gaithersburg, MD, 2008, pp. 1237–46.Google Scholar
  13. 13.
    P. J. Maziasz: J. Met., 1989, vol. 41, pp. 14–20.Google Scholar
  14. 14.
    T. Sourmail: Mater. Sci. Technol., 2001, vol. 17, pp. 1–14.Google Scholar
  15. 15.
    T. Sourmail and H.K.D.H. Bhadeshia: Metall. Mater. Trans. A, 2005, vol. 36A, pp. 23–34.CrossRefGoogle Scholar
  16. 16.
    Quality and Properties of NF709 Austenitic Stainless Steel for Boiler Tubing Applications, Nippon Steel Corporation, Tokyo, 1996Google Scholar
  17. 17.
    J.P. Shingledecker, P.J. Maziasz, N.D. Evans, and M.J. Pollard: Proc. Symp. Sponsored by Materials Science Technology 2005, R.S. Mishra, J.C. Earthman, S.V. Raj, and R. Viswanathan, eds., Pittsburgh, PA, 2005, pp. 25–28Google Scholar
  18. 18.
    Y. Yamamoto, M. Takeyama, Z.P. Lu, C.T. Liu, N.D. Evans, P.J. Maziasz, and M.P. Brady: Intermetallics, 2008, vol. 16 (3), pp. 453–62.CrossRefGoogle Scholar
  19. 19.
    Y. Yamamoto, M.P. Brady, Z.P. Lu, C.T. Liu, M. Takeyama, P.J. Maziasz, and B.A. Pint: Metall. Mater. Trans. A, 2007, vol. 38A, pp. 2737–46.CrossRefADSGoogle Scholar
  20. 20.
    R.W. Swindeman, P.J. Maziasz, E. Bolling, and J.F. King: Oak Ridge National Laboratory Report No. ORNL-6629/P1, Oak Ridge, TN, 1990.Google Scholar
  21. 21.
    R.W. Swindeman and P.J. Maziasz: Proc. 1st Int. Conf. on Heat-Resistant Materials, K. Natesan and D.J. Tillack, eds., ASM INTERNATIONAL, Materials Park, OH, 1991, pp. 251–59.Google Scholar
  22. 22.
    F.H. Stott, G.C. Wood, and J. Stringer: Oxid. Met., 1995, vol. 44 (1–2), pp. 113–45.CrossRefGoogle Scholar
  23. 23.
    C. Wagner: Corros. Sci., 1965, vol. 5, pp. 751–64.CrossRefGoogle Scholar
  24. 24.
    M. Kikuchi, M. Sakakibara, Y. Otoguro, H. Mimura, S. Araki, and T. Fujita: in High Temperature Alloys: Their Exploitable Potential, J.B. Marriott, M. Merz, J. Nihoul, and J. Ward, eds., Elsevier Applied Science, London, 1985, pp. 267–76.Google Scholar
  25. 25.
    D.J. Powell, R. Pilkington, and D.A. Miller: Acta Metall., 1988, vol. 36, pp. 713–24.CrossRefGoogle Scholar
  26. 26.
    D. Satyanarayana, G. Malakondaiah, and D. Sarma: Mater. Charact., 2001, vol. 47, pp. 61–65.CrossRefGoogle Scholar
  27. 27.
    D. Satyanarayana, G. Malakondaiah, and D. Sarma: Mater. Sci. Eng., A, 2002, vol. 323, pp. 119–28.CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society and ASM International 2009

Authors and Affiliations

  • Y. Yamamoto
    • 1
    • 2
  • M.L. Santella
    • 1
  • M.P. Brady
    • 1
  • H. Bei
    • 1
  • P.J. Maziasz
    • 1
  1. 1.Materials Science and Technology DivisionOak Ridge National LaboratoryOak RidgeUSA
  2. 2.Department of Materials Science and EngineeringUniversity of TennesseeKnoxvilleUSA

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