FRACTURE OF STRUCTURAL ALLOYS AT TEMPERATURES APPROACHING ABSOLUTE ZERO

With the advent of superconducting electrical machinery we face for the first time a demand for fail-safe, efficiently designed structures that must be cooled with liquid helium to temperatures as low as 4 k. Fracture tests in this environment should provide information of current scientific interest as well as data of engineering utility. The traditional notched tensile and Charpy tests provide only qualitative indications of crack tolerance, while the KIC test applies only to high strength alloys, which fail in the elastic range. None of these parameters are well suited for characterizing the ductile and tough austenitic alloys which offer maximum fracture resistance at cryogenic temperatures. In this study, J-integral and KIC tests were used to characterize the fracture behaviour of 14 alloys at temperatures from 295 to 4 K. JIC is believed to be a material constant, applicable in both the elastic and elastic-plastic cases. Thus, the newly developed JIC criterion offers a method for comparing the fracture behaviour of low, medium, and high strength alloys--a task that was problemmatic in the past.

  • Supplemental Notes:
    • Presented at Fracture 1977, Volume 3, Waterloo, Canada, June 19-24, 1977.
  • Corporate Authors:

    National Bureau of Standards

    14th Between E Street and Constitution Avenue, NW
    Washington, DC  United States  20234
  • Authors:
    • Tobler, R L
  • Publication Date: 1977

Media Info

  • Features: References;
  • Pagination: p. 839-845

Subject/Index Terms

Filing Info

  • Accession Number: 00182525
  • Record Type: Publication
  • Source Agency: National Bureau of Standards
  • Report/Paper Numbers: Vol 3, ICF 4, R-1027
  • Files: TRIS
  • Created Date: Oct 12 1978 12:00AM