STP1245

    Correlation of Transmission Electron Microscopy (TEM) Microstructure Analysis and Texture with Nodular Corrosion Behavior for Zircaloy-2

    Published: Jan 1994


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    Abstract

    Zircaloy-2 controlled chemistry tubes were fabricated using different tubeshell annealing temperatures and tube reduction schedules. The results of this set of materials was previously presented in ASTM STP 1132. This paper presents new results from texture and transmission electron microscopy (TEM) microstructure investigations on the same set of materials.

    Samples with various processing histories were examined by TEM microscopy to characterize the intermetallic precipitate distributions and matrix solute concentration. Matrix concentration profiles across a 2-μm length were obtained in scanning transmission electron microscopy (STEM) mode using an electron beam spot of approximately 0.07 μm on high and low corrosion resistant material. The influence of texture on corrosion was also examined by fabricating specimens with radial textures (fr) values from approximately 0.3 to 0.6.

    The results show that the tube reduction schedule has a very significant influence on nodular corrosion behavior. The accumulated reduction factor was established to define the influence of deformation during tube reducing on texture. High fr on the final cladding suppressed the nodular corrosion behavior regardless of the precipitate size. This leads to conflicting evidence on the role of precipitate size and corrosion behavior. Micro-zones of solute segregation in the matrix were also detected above the solubility limits of α-zirconium on some final cladding specimens.

    Keywords:

    zirconium, zirconium alloys, nuclear materials, nuclear applications, nodular corrosion, texture (materials), deformation (materials), transmission electron microscopy, intermetallic precipitates


    Author Information:

    Herb, BJ
    Process engineer, retired, Teledyne Wah Chang Albany, Albany, OR

    McCarthy, JM
    Senior research engineer, Oregon Graduate Institute of Science and Technology, Beaverton, OR

    Wang, CT
    Process engineer, retired, Teledyne Wah Chang Albany, Albany, OR

    Ruhmann, H
    Siemens AG, Power Generation Group (KWU), Erlangen,


    Paper ID: STP15201S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP15201S


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