Stress Accelerated Grain Boundary Oxidation of Incoloy Alloy 908 in High Temperature Oxygenous Atmospheres

  • M. M. Morra
  • S. Nicol
  • L. Toma
  • I. S. Hwang
  • M. M. Steeves
  • R. G. Ballinger
Part of the An International Cryogenic Materials Conference Publication book series (ACRE, volume 40)


Heat treatments of magnets utilizing INCOLOY® alloy 908* as a conduit have been successfully performed in vacuum. Similar experience with large scale heat treatment in an inert gas environment such as argon is lacking. Prior studies on other nickel-iron base superalloys that are susceptible to intergranular oxygen embrittlement and cracking emphasize the importance of establishing an allowable oxygen impurity level in argon for alloy 908. Initial screening using C-ring tests have shown that cracking can occur in an argon atmosphere if proper control over the oxygen impurity level is not maintained. Stress-rupture tests performed in air show that this material is susceptible to intergranular cracking in notched sections when subjected to stresses in excess of 300 MPa for a stress-concentration factor (Kt) of 4.1 at the notch. A series of stress-rupture tests are now underway on alloy 908 base metal in oxygen containing argon atmospheres. A double-edged notched test specimen design is used to determine the rupture time as functions of applied stress, temperature and oxygen concentration. The oxygen concentration at the specimen notches is continuously measured using an electrochemical sensor. Initial results suggest that an argon atmosphere does yield an improved stress-rupture life over air at low oxygen concentrations. Results are discussed to establish whether the possibility for heat treatments in argon exists and if so what guidelines must be used for successful heat treatment.


Intergranular Crack Rupture Life International Thermonuclear Experimental Reactor Fatigue Crack Growth Behavior Inco Alloy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    R.H. Bricknell and D.A. Woodford, “Environmental Effects in the Iron Base Alloy IN903A”, General Electric Company, Schenectady, NY, Report Number 80CRD268, (1980).Google Scholar
  2. 2.
    D.F. Smith, E.F. Clustworthy, D.G. Tipton, and W.L. Mankins, Improving the notch-rupture strength of low-expansion superalloys, in: “Superalloys 1980”, 521, ASM, Metals Park, OH (1980).CrossRefGoogle Scholar
  3. 3.
    D.A. Woodford and R.H. Bricknell, Environmental embrittlement of high temperature alloys by oxygen, in: “Treatise on Materials Science and Technology”, C.L. Briant and S.K. Banerji, eds., Academic Press, NY, (1983)Google Scholar
  4. 4.
    R.H. Bricknell and D.A. Woodford, Grain boundary embrittlement of the iron-base superalloy IN903A, Met. Trans., 12A: 1673 (1981).CrossRefGoogle Scholar
  5. 5.
    M.M. Morra, R.G. Ballinger, J.L. Martin, M.O. Hoenig, and M.M. Steeves, Incoloy® 9XA, a new low coefficient of thermal expansion sheathing alloy for use in ICCS magnets, in: “Advances in Cryogenic Engineering Materials”, A.F. Clark and R.P. Reed, eds., 34/157 (1987).Google Scholar
  6. 6.
    M.M. Morra, “Alloy 908, A New High Strength, Low Coefficient of Thermal Expansion Alloy for Cryogenic Applications”, S.M. Thesis, Massachusetts Institute of Technology, February, (1989).Google Scholar
  7. 7.
    M.M. Mona, R.G. Ballinger, and I.S. Hwang, Incoloy 908, a low coefficient of expansion alloy for high strength cryogenic applications: part 1-physical metallurgy, Met.Trans. A, 3177 (December 1992).Google Scholar
  8. 8.
    M.M. Steeves, T.A. Painter, M. Takayasu, R.N. Randall, J.E. Tracey, I.S. Hwang, and M.O. Hoenig, The US demonstration poloidal coil, IEEE Trans. Mag., 27, No. 2: 2369 (March 1991).CrossRefGoogle Scholar
  9. 9.
    M.M. Steeves, M.O. Hoenig, M. Takayasu, R.N. Randall, J.E. Tracey, J.R. Hale, M.M. Mona, I. Hwang and P. Marti, Progress in the manufacture of the US-DPC test coil, IEEE Trans. Mag., 25, No. 2: 1738 (March 1989).CrossRefGoogle Scholar
  10. 10.
    M.M. Steeves, T.A. Painter, J.E. Tracey, M.O. Hoenig, M. Takayasu, R.N. Randall, M.M. Mona, I.S. Hwang and P. Marti, Further progress in the manufacture of the US-DPC test coil, in: “Proceedings, 11th International Conference on magnet Technology”, Tsukuba, Japan, (1989).Google Scholar
  11. 11.
    S. Floreen, Effects of environment on intermediate temperature crack growth in superalloys, in: “Micro and Macro Mechanics of Crack Growth”, K. Sadananda, B.B. Rath, and D.J. Michel, eds., The Metallurgical Society of AIME, 177, (1981).Google Scholar
  12. 12.
    S. Floreen and R.H. Kane, An investigation of the creep-fatigue-environment interaction in a Ni-base superalloy, Fatigue of Eng. Mat. and Struct., 2: 401.Google Scholar
  13. 13.
    S. Floreen and R.H. Kane, Effects’ of environment on high temperature fatigue crack growth in a superalloy, Met. Trans. A, 10A: 1745 (November 1979).Google Scholar
  14. 14.
    D. Zheng and H. Ghonem, Oxidation-assisted fatigue crack growth behavior in alloy 718 - part II. applications, Fatigue Fract. Engng. Mater. Struct., 14, No. 7: 761 (1991).CrossRefGoogle Scholar
  15. 15.
    D.J. Wilson, Relationship of mechanical characteristics and microstructural features to the time-dependent edge-notch sensitivity of inconel 718 sheet“, J. Eng. Mater. and Tech., 112 (April 1973).Google Scholar
  16. 16.
    D. Zheng and H. Ghonem, Influence of prolonged thermal exposure on intergranular fatigue crack growth behavior in alloy 718 at 650 °C, Met. Trans. A., 23A: 3169 (November 1992).CrossRefGoogle Scholar
  17. 17.
    A. Diboine and A. Pineau, Creep crack initiation and growth in inconel 718 alloy at 650 °C, Fatigue Fract. Engng. Mater. Struct., 10, No. 2: 414 (1987).CrossRefGoogle Scholar
  18. 18.
    J.P. Pedron and A. Pineau, The effect of microstructure and environment on the crack growth behavior of inconel 718 alloy at 650 °C under fatigue, creep and combined loading, Mater. Sci. and Eng., 56: 143 (1982).CrossRefGoogle Scholar
  19. 19.
    H. Ghonem and D. Zheng, Depth of intergranular oxygen diffusion during environment-dependent fatigue crack growth in alloy 718, Mater. Sci. and Eng., A150: 151 (1992).CrossRefGoogle Scholar
  20. 20.
    K. Sadananda and P. Shahinian, The effect of environment on the creep crack growth behavior of several structural alloys, Mater. Sci. and Eng., 43: 159 (1980).CrossRefGoogle Scholar
  21. 21.
    H.H. Smith and D.J. Michel, Fatigue crack propagation and deformation mode in alloy 718 at elevated temperatures, in: “Ductility and Toughness Considerations in Elevated Temperature Service, MPC8”, G.V. Smith, ed., The American Society of Mechanical Engineers, NY, 225, (1978).Google Scholar
  22. 22.
    K. Sato and T. Ohno, Development of low thermal expansion superalloys, in: “Superalloys 1992”, 247, ASM Metals Park, OH (1992).Google Scholar
  23. 23.
    E.A. Wanner and D.A. DeAntonio, Development of a new controlled thermal expansion superalloy with improved oxidation resistance, in: “Superalloys 1992”, 237, ASM Metals Park, OH (1992).Google Scholar
  24. 24.
    NJ. Grant and A.W. Mullendore, “Deformation and Fracture at Elevated Temperatures”, The MIT Press, Cambridge, MA (1965)Google Scholar
  25. 25.
    R.M. Goldhoff, The evaluation of elevated temperature creep and rupture strength data: an historical perspective“, in: ”Characterization of Materials for Service at Elevated Temperatures, MPC-7“, G.V. Smith, ed., American Society of Mechanical Engineers, NY, 247 (1978).Google Scholar
  26. 26.
    H.E. Boyer, ed., “Atlas of Creep and Stress-Rupture Curves”, ASM Int., Metals Park, OH, 1.1–2.11 (1988).Google Scholar
  27. 27.
    H.E. Evans, “Mechanisms of Creep Fracture”, Elsevier Science Publishing Co., London (1984).Google Scholar
  28. 28.
    C.J. Moss and J.W. Martin, The effect of grain boundary y’ precipitation on the stress rupture behavior of nimonic PE16, Materials Forum, 15: 324 (1991).Google Scholar
  29. 29.
    D. J. Wilson, Sensitivity of the creep-rupture properties of waspaloy sheet to sharp-edged notches in the temperature range 1000–1400 deg F, J. Basic Eng., 13 (March 1972).Google Scholar
  30. 30.
    S. Nicol, “Stress-Rupture Properties of Incoloy 908 in Air”, B.S.M.E Thesis, Worcester Polytechnic Institute, (July 1993).Google Scholar
  31. 31.
    I.S. Hwang, R.G. Ballinger, M.M. Morra, and M.M. Steeves, Mechanical properties of incoloy 908 - an update, in: “Advances in Cryogenic Engineering (Materials)”, 38, F. Fickett and R.P. Reed, eds., Plenum Press, NY (1992).Google Scholar
  32. 32.
    I.P. Vasatis and R.M. Pelloux, “dc potential drop technique in creep stress rupture testing, J. of Met., 44 (October 1985).Google Scholar
  33. 33.
    ASTM Book of Standards, (E292–83).Google Scholar
  34. 34.
    J.H. Weber and H. Sizek, Private Communication from Inco Alloys Int., Huntington, WV, (May 27, 1993 ).Google Scholar
  35. 35.
    G.F. Vander Voort, “Metallography Principles and Practice”, McGraw-Hill, NY (1984).Google Scholar
  36. 36.
    M.S. Loveday, Practical aspects of testing circumferential notch specimens at high temperature, in: “Techniques for Multiaxial Creep Testing”, Elsevier, NY, 177 (1986).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • M. M. Morra
    • 1
  • S. Nicol
    • 1
  • L. Toma
    • 2
  • I. S. Hwang
    • 1
  • M. M. Steeves
    • 2
  • R. G. Ballinger
    • 3
  1. 1.Department of Materials Science and EngineeringMassachusetts Institute of TechnologyCambridgeUSA
  2. 2.Plasma Fusion CenterMassachusetts Institute of TechnologyCambridgeUSA
  3. 3.Departments of Nuclear Engineering and Materials Science and EngineeringMassachusetts Institute of TechnologyCambridgeUSA

Personalised recommendations