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Metallurgical and Materials Transactions A

, Volume 36, Issue 7, pp 1777–1791 | Cite as

The fracture toughness and toughening mechanisms of wrought low carbon arc cast, oxide dispersion strengthened, and molybdenum-0.5 pct titanium-0.1 pct zirconium molybdenum plate stock

  • B. V. Cockeram
Article

Abstract

The high-temperature strength and creep resistance of low carbon arc cast (LCAC) unalloyed molybdenum, oxide dispersion strengthened (ODS) molybdenum, and molybdenum-0.5 pct titanium-0.1 pct zirconium (TZM) molybdenum have attracted interest in these alloys for various high-temperature structural applications. Fracture toughness testing of wrought plate stock over a temperature range of −150 °C to 1000 °C using bend, flexure, and compact tension (CT) specimens has shown that consistent fracture toughness results and transition temperatures are obtained using subsized 0.5T bend and 0.18T disc-CT specimens. Although the fracture toughness values are not strictly valid in accordance with all ASTM requirements, these values are considered to be a reasonable measure of fracture toughness. Ductile-to-brittle transition temperature (DBTT) values were determined in the transverse and longitudinal orientations for LCAC (200 °C and 150 °C, respectively), ODS (<room temperature and −150 °C), and TZM (150 °C and 100 °C). At test temperatures > DBTT, the fracture toughness values for LCAC ranged from 45 to 175 MPa√m, TZM ranged from 74 to 215 MPa√m, and the values for ODS ranged from 56 to 149 MPa√m. No temperature dependence was resolved within the data scatter for fracture toughness values between the DBTT and 1000 °C. Thin sheet toughening is shown to be the dominant toughening mechanism, where crack initiation/propagation along grain boundaries leaves ligaments of sheetlike grains that are pulled to failure by plastic necking. Specimen-to-specimen variation in the fraction of the microstructure that splits into thin sheets is proposed to be responsible for the large scatter in toughness values at test temperatures > DBTT. A finer grain size is shown to result in a higher fraction of thin sheet ligament features at the fracture surface. As a result finer grain size materials such as ODS molybdenum have a lower DBTT.

Keywords

Fracture Toughness Material Transaction Compact Tension Oxide Dispersion Strength Compact Tension Specimen 
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.

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References

  1. 1.
    J.B. Lambert and J.J. Rausch: Metals Handbook, vol. 2, Non-Ferrous Alloys and Special-Purpose Materials, ASM INTERNATIONAL, Materials Park, OH, 1992, pp. 557–82.Google Scholar
  2. 2.
    R.E. Gold and D.L. Harrod: J. Nucl. Mater., 1979, vols. 85–86, pp. 805–15.CrossRefGoogle Scholar
  3. 3.
    B.L. Cox and F.W. Wiffen: J. Nucl. Mater., 1979, vols. 85–86, pp. 901–05.CrossRefGoogle Scholar
  4. 4.
    K. Furuya and J. Moteff: J. Nucl. Mater., 1981, vol. 99, pp. 306–16.CrossRefGoogle Scholar
  5. 5.
    M. Scibetta, R. Chaouadi, and J.L. Puzzolante: J. Nucl. Mater., 2000, vols. 283–287, pp. 455–60.CrossRefGoogle Scholar
  6. 6.
    G.R. Smolik, D.A. Petti, and S.T. Schuetz: J. Nucl. Mater., 2000, vols. 283–287, pp. 1458–62.CrossRefGoogle Scholar
  7. 7.
    B.V. Cockeram: Metall. Mater. Trans. A, 2002, vol. 33A, pp. 3685–3707.Google Scholar
  8. 8.
    J.A. Shields, P. Lipetzky, and A.J. Mueller: Proc. 15th Int. Plansee Seminar, G. Kneringer, P. Rodhammer, and H. Wildner, eds., Plansee Holding AG, Reutte, Austria, 2001, vol. 4, pp. 187–99.Google Scholar
  9. 9.
    ASTM B386-91, ASTM, Philadelphia, PA, 1997.Google Scholar
  10. 10.
    R. Bianco, R.W. Buckman, Jr., and C.B. Geller: U.S. Patent 5,868,876, Feb. 9, 1999.Google Scholar
  11. 11.
    A.J. Mueller, J.A. Shields, and R.W. Buckman, Jr.: Proc. 15th Int. Plansee Seminar, G. Kneringer, P. Rodhammer, and H. Wildner, eds., Plansee Holding AG, Reutte, Austria, 2001, vol. 1, pp. 485–97.Google Scholar
  12. 12.
    R. Bianco and R.W. Buckman, Jr.: 1995 Spring ASM/TMS Symp. on High Temperature Materials, May 19, 1995, GE CR&D Center, Schenectady, NY (available as WAPD-T-3073, DOE/OSTI, Oak Ridge, TN, 1995).Google Scholar
  13. 13.
    R. Bianco and R.W. Buckman, Jr.: in Molybdenum and Molybdenum Alloys, A. Crowson, E.S. Chen, J.A. Shields, and P.R. Subramanian, eds., TMS, Warrendale, PA, 1998, pp. 125–42.Google Scholar
  14. 14.
    A.Yu, Koval, A.D. Vasilev, and S.A. Firstov: Int. J. Refractory Met. Hard Mater., 1997, vol. 15, pp. 223–26.CrossRefGoogle Scholar
  15. 15.
    M. Danylenko: in Modeling the Mechanical Response of Structural Materials, E.M. Taleff and R.K. Mahidhara, eds., TMS, Warrendale, PA, 1997, pp. 229–35.Google Scholar
  16. 16.
    M. Rödig, H. Derz, G. Pott, and B. Werner: Proc. 14th Int. Plansee Seminar, G. Kneringer, P. Rödhammer, and P. Wilharitz, eds., Metallwerk Plansee, Reutte, Austria, 1997, vol. 1, pp. 781–91.Google Scholar
  17. 17.
    D.L. Chen, B. Weiss, R. Stickler, M. Witwer, G. Leichtfried, and H. Hödl: High Temp. Mater. Processes, 1994, vol. 13, pp. 75–85.Google Scholar
  18. 18.
    D.L. Chen, B. Weiss, R. Stickler, M. Witwer, and G. Leichtfried: Proc. 13th Int. Plansee Seminar, H. Bildstein and R. Eck, eds., Metallwerk Plansee, Reutte, Austria, 1993, vol. 1, pp. 621–31.Google Scholar
  19. 19.
    M. Semchyshen and R.Q. Barr: J. Less-Common Met., 1966, vol. 11, pp. 1–13.CrossRefGoogle Scholar
  20. 20.
    C.W. Marschall and F.C. Holden: High Temperature Refractory Metals, Gordon-Breach Science Publishers, New York, NY, 1964, pp. 129–59.Google Scholar
  21. 21.
    H.E. Romine: NWL Report No. 1873, U.S. Naval Weapons Laboratory, Dahlgren, VA, 1963.Google Scholar
  22. 22.
    ASTM E1823-96, ASTM, Philadelphia, PA, 1996.Google Scholar
  23. 23.
    ASTM E1820-01, ASTM, Philadelphia, PA, 2001.Google Scholar
  24. 24.
    ASTM E399-90, ASTM, Philadelphia, PA, 1997.Google Scholar
  25. 25.
    B.V. Cockeram: Surf. Coatings Technol., 1998, vols. 108–109, pp. 377–84.CrossRefGoogle Scholar
  26. 26.
    B.V. Cockeram: Metal. Mater. Trans. A, 2002, vol. 33A, pp. 33–56.CrossRefGoogle Scholar
  27. 27.
    A. Lawley, J. Van den Sype, and R. Maddin: J. Inst. Met., 1962–1963, vol. 91, pp. 23–27.Google Scholar
  28. 28.
    G.W. Brock: Trans. TMS-AIME, 1961, vol. 221, pp. 1055–62.Google Scholar
  29. 29.
    W.D. Klopp: J. Less Common Met., 1975, vol. 42 pp. 261–78.CrossRefGoogle Scholar
  30. 30.
    J. Wadsworth, T.G. Nieh, and J.J. Stephens: Scripta Metall., 1986, vol. 20, pp. 637–42.CrossRefGoogle Scholar
  31. 31.
    J. Wadsworth, C.M. Packer, P.M. Chewey, and W.C. Coons: Metal. Mater. Trans. A, 1984, vol. 15A, pp. 1741–52.Google Scholar
  32. 32.
    S. Suresh and J.R. Brockenbrough: Acta Metall., 1988, vol. 36, pp. 1455–70.CrossRefGoogle Scholar
  33. 33.
    R. W. Hertzberg: Deformation and Fracture Mechanics of Engineering Materials, 2nd ed., John Wiley & Sons, New York, NY, 1983, pp. 269–348.Google Scholar
  34. 34.
    A. Kumar and B.L. Eyre: Proc. R. Soc. London, 1980, vol. A370, pp. 431–58.Google Scholar
  35. 35.
    H. Kurishita and H. Yoshinaga: Mater. Forum, 1989, vol. 13, pp. 161–73.Google Scholar
  36. 36.
    J.B. Brosse, R. Fillit, and M. Biscondi: Scripta Metall., 1981, vol. 15, pp. 619–23.CrossRefGoogle Scholar
  37. 37.
    K.S. Chan: Metal. Trans. A, 1989, vol. 20A, pp. 155–64.Google Scholar
  38. 38.
    K.S. Chan: Metal. Trans. A, 1989, vol. 20A, pp. 2337–44.Google Scholar

Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 2005

Authors and Affiliations

  • B. V. Cockeram
    • 1
  1. 1.the Bechtel-Bettis Atomic Power LaboratoryWest Mifflin

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