STP824

    Influence of Crystallographic Texture and Test Temperature on Initiation and Propagation of Iodine Stress-Corrosion Cracks in Zircaloy

    Published: Jan 1984


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    Abstract

    The effect of crystallographic texture on the initiation and the propagation of iodine stress-corrosion cracks in unirradiated Zircaloy is examined. Internal gas pressurization tests with iodine are performed on three tubing lots with different textures at 320 and 390°C. These smooth-bar tests yield data for time-to-failure and strain at failure versus hoop stress. Double-cantilever beam specimens provide crack velocity versus K and KISCC data at 300 to 310°C as a function of the texture ahead of the propagating crack. Smooth-bar threshold stress is strongly texture dependent over the temperature range 320 to 390°C. Basal poles oriented toward the direction of applied stress, such as a tangential tubing texture, result in faster crack propagation, lower KISCC, and a lower smooth-bar threshold stress. Plastic strain is shown to play an important role in crack intiation. The implication of texture and plastic strain effects on iodine SCC susceptibility of irradiated material is considered. Linear elastic fracture mechanics is found to be invalid for the short cracks observed in Zircaloy cladding.

    Keywords:

    Zircaloy, iodine stress-corrosion cracking, crystallographic texture, crack initiation, crack propagation


    Author Information:

    Knorr, DB
    Olin Corp., Metals Research Laboratories, New Haven, Conn.

    Peltier, JM
    Research assistant and professor of materials engineering, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Mass.

    Pelloux, RM
    Research assistant and professor of materials engineering, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Mass.


    Paper ID: STP34498S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP34498S


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