STP551

    Irradiation Damage Recovery in Some Zirconium Alloys

    Published: Jan 1974


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    Abstract

    The recovery of irradiation damage in a number of zirconium alloys has been studied by means of hardness measurements. The experiments were designed to examine the effect of different solutes (copper, aluminum, titanium, niobium, molybdenum) and metallurgical condition on the stability of irradiation-induced defect clusters.

    Sheet specimens have been irradiated at 50°C to a fast neutron fluence of 5.5 × 1019 neutrons (n)/cm2 and the hardness changes studies during isochronal annealing. The specimens were heat treated prior to irradiation as follows: (a) well annealed, to approach the equilibrium structure and (b) β-quenched. Most of the annealed alloys recovered in one stage over a temperature range of about 100°C within the range 300 to 460°C.

    The behavior of the β-quenched specimens was more complicated due to the simultaneous annealing of the martensitic substructure and solute precipitation. The presence of a high supersaturation of niobium or molybdenum resulted in large hardness increments as a result of irradiation. This is believed to result from precipitation of the solute on a fine scale or to the formation of solute/radiation damage complexes.

    Transmission electron microscopy under kinematical conditions revealed the presence of “black spot” images, 30 to 70Å (3 to 7 nm) in diameter in a concentration of ∼5 × 1016/cm3 The smallest images could not be clearly distinguished owing to the presence of a thin oxide film on the surfaces of thin foil specimens. Some possible implications of these results to the problem of in-reactor creep are discussed.

    Keywords:

    zirconium alloys, irradiation, radiation damage, electron microscopy, neutron irradiation, in-reactor creep


    Author Information:

    Carpenter, GJC
    Research metallurgist and research technologist, Materials Science Branch, Atomic Energy of Canada Limited, Chalk River Nuclear Laboratories, Chalk River, Ontario

    Watters, JF
    Research metallurgist and research technologist, Materials Science Branch, Atomic Energy of Canada Limited, Chalk River Nuclear Laboratories, Chalk River, Ontario


    Paper ID: STP32128S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP32128S


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