STP1125

    Dislocation Loop Formation in Ion-Irradiated Polycrystalline Spinel and Alumina

    Published: Jan 1992


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    Abstract

    The microstructure of magnesium aluminate spinel (MgAl2O4) and alumina (Al2O3) has been examined with transmission electron microscopy following ion irradiation to damage levels of 0.1 to 5 keV/atom (1 to 50 dpa) at room temperature and 650°C. The ion irradiation produced interstitial dislocation loops of types α/4(110}{110} and α/4{110){111} in spinel along with a very low density of α/6(111){111} loops. Dislocation loops of types α/3[0001] (0001) and α/3[1100]{1100} were tentatively identified in alumina. The loop size increased and the density decreased gradually with increasing fluence in spinel irradiated at 650°C, with the net result that the concentration of interstitials contained in the loops remained nearly constant at ∼0.1 at%. Defect-free regions were observed adjacent to grain boundaries, and the irradiated surface in spinel irradiated at 650°C. The denuded zone width was very small for spinel irradiated at 25°C and Al2O3 irradiated at 650°C. For a given irradiation temperature, the loops in spinel were larger and of much lower density than the loops in Al2O3.

    Keywords:

    ion irradiation, microstructure, dislocation loops, ceramics, spinel, alumina


    Author Information:

    Zinkle, SJ
    Research staff member, Oak Ridge National Laboratory, Oak Ridge, TN


    Paper ID: STP17908S

    Committee/Subcommittee: E10.08

    DOI: 10.1520/STP17908S


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