Fracture toughness of hydrided Zircaloy-4 sheet under through-thickness crack growth conditions

P. A. Raynaud, D. A. Koss, A. T. Motta, K. S. Chan

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


The susceptibility of fuel cladding to failure in the case of a postulated reactivity-initiated accident may be determined by crack initiation within a hydride blister or rim and subsequent crack growth through the thickness of the cladding. This study has determined the fracture toughness of hydrided coldworked stress relieved Zircaloy-4 sheet subject to through-thickness crack growth at both 25 and 300°C. The experimental approach utilizes a novel procedure in which a narrow linear strip of brittle hydride blister across the specimen width creates a well-defined precrack upon initial loading. The subsequent crack growth resistance is then characterized by four-point bending of the specimen and an elastic-plastic fracture mechanics analysis. At room temperature, the through-thickness fracture toughness (Kq) is sensitive to the orientation of the hydride platelets and Kq≅25 MPa√m for crack growth through a mixed in-plane/out-of-plane hydride field. In contrast, Kq is much higher (≅75 MPa√m) when the hydride platelets are oriented predominantly in the plane of the sheet and therefore normal to both the crack plane and the crack growth direction. At 300°C, the material exhibits greater ductility as the hydride particles within the matrix resist fracture such that Kq≅83 MPa√m, despite the much lower flow stress of the material.

Original languageEnglish (US)
JournalJournal of ASTM International
Issue number1
StatePublished - Jan 2008

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • General Materials Science
  • Nuclear Energy and Engineering
  • General Engineering
  • Public Health, Environmental and Occupational Health


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