STP754: Effect of Texture on Hydride Reorientation and Delayed Hydrogen Cracking in Cold-Worked Zr-2.5Nb

    Coleman, CE
    Metallurgist, Atomic Energy of Canada Ltd., Chalk River Nuclear Laboratories, Chalk River, Ont.

    Pages: 19    Published: Jan 1982


    Abstract

    Hydride reorientation and delayed hydrogen cracking have been evaluated in specimens cut from the longitudinal and circumferential directions of cold-worked Zr-2.5Nb pressure tubes. In this material basal plane normals were highly concentrated in the circumferential direction. In longitudinal specimens hydrides did not reorient, cracks were not initiated, and artificial cracks grew slowly and only at KI>15MPa·m, whereas in circumferential specimens hydrides reoriented easily, cracks could be initiated, and grew at KI>4.5MPa·m25 25 times faster than cracks at the same KI in longitudinal specimens. Reorientation of hydrides is not necessary for delayed hydrogen cracking, but the degree of reorientation controls cracking susceptibility. Crystallographic texture regulates hydride reorientation and a rotation of basal plane normals from the circumferential to radial direction should reduce the susceptibility of Zr-2.5Nb and other zirconium alloys to delayed hydrogen cracking.

    Keywords:

    nuclear industry, zirconium, zirconium alloys, temperature cycling, hydride reorientation, crack initiation, crack propagation, texture


    Paper ID: STP37439S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP37439S


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