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Fracture and Tensile Properties of Boron Added Ni-Base Superalloy at 7 and 4.2 K, and the Effect of 13 Tesla Field

  • A. Nyilas
  • K. Shibata
  • W. Specking
  • H. Kiesel
Chapter

Abstract

Tensile and fracture properties of an aged, boron added Ni-base superalloy are investigated in liquid helium and at 7 K. The 200 hour and 923 K aging of this superalloy specimens are performed under observation of an in situ oxygen emf sensor. For tensile tests carried out under 13 tesla magnetic field a new 4 K rig is designed capable to be fitted into an existing Nb3Sn 13.5 tesla split coil. The tests carried out at 7 K are performed with a 25 kN capacity servohydraulic machine using a helium flow cryostat. To obtain the possible magnetic field effect on tensile behavior extensive tests are carried out with titanium as non magnetic reference material. Fracture tests are conducted using 4 – 6 mm diameter EDM-notched round bars at 7 K and at 4.2 K with or without magnetic field using the JETT fracture test (J evaluation on tensile test). The obtained results indicate so far that the different stiffness of the used testing systems play a significant role for the total elongation at fracture for tensile behavior as well as for JETT results. In addition, elasticplastic J-tests are performed at 4.2 K using 15 mm thick standard compact tension specimens and the obtained results are compared with current JETT test results.

Keywords

Fracture Toughness Oxygen Partial Pressure Liquid Helium Total Elongation 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.
    L. Flower, Nickel-iron alloy designed for fusion-reactor components, Advanced Materials & Processes vol. 147, No 4, (1995), p.9Google Scholar
  2. 2.
    M. M. Morra, Stress accelerated grain boundary oxidation of Incoloy alloy 908 in high temperature oxygenous atmosphere, Doctoral thesis, Massachusetts Institute of Technology (1995)Google Scholar
  3. 3.
    T. Kato et al., Avoidance method study for SAGBO cracking during heat treatment of a ITER CS model coil conductor using Incoloy 908 jacket, in: “Advances in Cryogenic Engineering (Materials),” vol. 44, Plenum, New York (1998) p. 9Google Scholar
  4. 4.
    M. K. Miller et al., Characterization of the effects of boron and phosphorus additions to the nickel based superalloy 718, J. de Physique IV, C5, 6 (1996) p. 241Google Scholar
  5. 5.
    W. D. Cao and R. L. Kennedy, in: “Superalloys 718, 625, 706 and various derivatives,” Ed. By E. Loria, TMS, (1994), p. 463Google Scholar
  6. 6.
    H. J. T. Ellingham, Reducibility of oxides and sulphides, J. soc. Chem. Ind., Trans., (1944), 63 p. 125CrossRefGoogle Scholar
  7. 7.
    L. S. Darken and R. Gurry, in: “Physical chemistry of metals”, Mc. Graw Hill Book comp. (1953).Google Scholar
  8. 8.
    A. Nyilas, B. Obst, and A. Ulbricht, Simulations on jacket material failure of NET-superconductors by surface crack growth in 316LN Type materials at 12K, in: “Advances in Cryogenic Engineering (Materials),” vol. 40, Plenum, New York (1994) p. 1239Google Scholar
  9. 9.
    Nishimura, J. Yamamoto, and A. Nyilas, Fatigue crack growth of SUS 316 and weld joint with natural crack at 7 K, in: “Advances in Cryogenic Engineering (Materials),” vol. 44, Plenum, New York (1998) p.81Google Scholar
  10. 10.
    A. Nyilas, B. Obst, and D. R. Harries, Mechanical investigations on aged stainless steel and Incoloy 908 materials at 4.2 K and 7 K, in: “Advances in Cryogenic Engineering (Materials),” vol. 44, Plenum, New York (1998) p. 17Google Scholar
  11. 11.
    A. Nyilas, B. Obst, and A. Nishimura, Fracture mechanics investigations at 7 K of structural materials with EDM notched round and double edged — bars, in: “Advances in Cryogenic Engineering (Materials),” vol. 44, Plenum, New York (1998) p. 153Google Scholar

Copyright information

© Kluwer Academic/Plenum Publishers, New York 2000

Authors and Affiliations

  • A. Nyilas
    • 1
  • K. Shibata
    • 2
  • W. Specking
    • 1
  • H. Kiesel
    • 1
  1. 1.Institut für Technische PhysikForschungszentrum KarlsruheKarlsruheGermany
  2. 2.Tokyo UniversityTokyoJapan

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