STP458: The Effect of Orientation of Hydride Precipitates on the Fracture Toughness of Cold-Rolled Zircaloy-2 and 2.5Nb Zirconium

    Aitchison, I.
    Research Officer, Applied Materials Research Branch, Chalk River Nuclear Laboratories, Chalk River, Ont.

    Pages: 19    Published: Jan 1969


    The fracture toughness was estimated from single-edge notched specimens cut from three different orientations in slabs cold rolled to 20 and 40 percent reduction. In general the toughness decreased with hydrogen concentration—most rapidly in the first 100 ppm. However, specimens of 40 percent cold-rolled zirconium-niobium alloy cut so that the hydride platelets (which tend to lie parallel to the rolling plane) were parallel to the specimen plane, showed no decrease in toughness even with 500 ppm hydrogen. This is accounted for qualitatively.

    The fracture toughness for the Zircaloy-2 specimens was estimated both from fracture load and from crack-opening displacement. The results show the same trend, but both methods are inaccurate here because of significant stable crack propagation.


    embrittlement, zirconium alloys, Zircaloy-2, 2.5Nb zirconium, hydrogen, hydride, precipitate orientation, fracture toughness, crack-opening displacement, ductile fracture, delamination

    Paper ID: STP43826S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP43826S

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