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The Effect of Hardening via Long Range Order on the SCC and LTCP Susceptibility of a Nickel-30Chromium Binary Alloy

  • Tyler E. Moss
  • Catherine M. Brown
  • George A. YoungEmail author
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)

Abstract

The objective of this work is to evaluate the effect of hardening on the susceptibility of a Ni-30.7Cr wt% (Ni-33 at.%Cr) model alloy to stress corrosion cracking (SCC) and to low temperature crack propagation (LTCP). Unlike previous studies that employ cold work to induce susceptibility to SCC, this work utilizes isothermal ageing to produce the long range ordered Ni2Cr phase. Samples were aged at 475 °C for durations up to 3176 h in order to produce hardness values between 70-100 HRB. After ageing, precracked compact tension specimens were tested for susceptibility to primary water SCC and to LTCP. Samples aged for less than 200 h (70-80 HRB) showed very high resistance to SCC, while intergranular cracking was observed in samples aged for longer times. An activation energy of 129.7 ± 17.6 kJ/mol and a yield strength exponent of 6.4 ± 2.1 were measured for SCC growth at constant KI and ΔEcP conditions, consistent with observations for Alloy 690. Hardening via long range order had no measureable effect on the toughness of the alloy in air, but degraded the toughness and promoted intergranular fracture in hydrogen deaerated water (i.e. it caused susceptibility to LTCP). The similarity of the yield strength dependence to cold worked Alloy 690 and the common temperature dependence (~130 kJ/mol) to A600, X-750, A690, etc. suggests a common SCC mechanism for all these alloys. Hardening via long range order is a novel method to induce SCC susceptibility in Ni-30 wt%Cr alloys, which avoids some microstructural damage, inhomogeneity, and orientation effects that complicate testing of cold worked material.

Keywords

Stress corrosion cracking Low temperature crack propagation Long range order Alloy 690 EN52 

Notes

Acknowledgements

The Authors are indebted to John Mullen, who assisted with testing and data analysis; Bill Fichtner, Walt Fonda, Nelson Schwarting, and Rich Taylor who performed the SCC testing; Darryl Hull who performed the LTCP testing; and Reza Najafabadi for thoughtful insight and discussion throughout the testing and analysis.

References

  1. 1.
    H. Hanninen, I. Aho-Mantila, Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors (TMS, Michigan, 1988), pp. 77–92Google Scholar
  2. 2.
    D.J. Paraventi, W.C. Moshier, in 16th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, ed. by P. Andresen (NACE, Asheville, NC, 2013)Google Scholar
  3. 3.
    A. Marucco, G. Carcano, E. Signorelli, Materials Ageing and Component Life Extension (Italy, Milan, 1995), pp. 363–372Google Scholar
  4. 4.
    G.A. Young, D.R. Eno, Fontevraud 8 (SFEN, Avignon, FR, 2014)Google Scholar
  5. 5.
    E. Frely et al., Ann. Phys. 22(3), C2-137–C2-144 (1997)Google Scholar
  6. 6.
    L. Karmazin, J. Krejci, J. Zeman, Mater. Sci. Eng., A 183, 103–110 (1994)CrossRefGoogle Scholar
  7. 7.
    M.A. Abd-Elhady, G.A. Sargent, J. Mater. Sci. 21, 2657–2663 (1986)CrossRefGoogle Scholar
  8. 8.
    W.J. Mill, C.M. Brown, M.G. Burke, in Fracture Behavior of Alloy 600, Alloy 690, EN82H Welds, and EN52 Welds in Water (Report B-T-3303 Bechtel Bettis, 2007)Google Scholar
  9. 9.
    G.A. Young et al., Corrosion 72(11), 1433–1437 (2016)CrossRefGoogle Scholar
  10. 10.
    T.E. Moss, D.S. Morton, H.M. Mohr, Evaluation of the temperature dependence of alloy 690 and alloy 690 weld metal SCC growth in hydrogenated water, in 16th International Conference on Environmental Degradation of Materials in Nuclear Power Systems—Water Reactors (Ottawa, Ontario, Canada, 2015)Google Scholar
  11. 11.
    A.R. Jenks, G.A. White, P. Crooker, in Proceedings of the ASME 2017 Pressure Vessels and Piping Conference, PVP2017-65886 (Waikoloa, HI, 2017)Google Scholar
  12. 12.
    G.A. Young, J.D. Tucker, D.R. Eno, in 16th International Conference on Environmental Degradation of Materials in Nuclear Power Systems—Water Reactors (NACE, Asheville, NC, 2013)Google Scholar
  13. 13.
    S.M. Bruemmer, M.J. Olszta, N.R. Overman, M.B. Toloczko, in 17th International Conference on Environmental Degradation of Materials in Nuclear Power System—Water Reactors (Ottawa, Ontario, Canada, 2015)Google Scholar
  14. 14.
    B.J. Berkowitz, C. Miller, The effect of ordering on the hydrogen embrittlement susceptibility of Ni2Cr. Metall. Mater. Trans. A 11, 1877–1881 (1980)CrossRefGoogle Scholar
  15. 15.
    K. Miyata, Effect of hydrogen charging and dislocation behavior in Ni–Cr and Ni2Cr alloys. Metall. Mater. Trans. A 34, 1249–1257 (2003)CrossRefGoogle Scholar

Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Tyler E. Moss
    • 1
  • Catherine M. Brown
    • 2
  • George A. Young
    • 3
    Email author
  1. 1.Naval Nuclear LaboratoryBechtel Marine Propulsion CorporationNiskayunaUSA
  2. 2.Naval Nuclear LaboratoryBechtel Marine Propulsion CorporationWest MifflinUSA
  3. 3.Dominion Engineering Inc.RestonUSA

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