SYMPOSIA PAPER Published: 01 January 1992

Dislocation Loop Formation in Ion-Irradiated Polycrystalline Spinel and Alumina


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.

Author Information

Zinkle, SJ
Oak Ridge National Laboratory, Oak Ridge, TN
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Developed by Committee: E10
Pages: 749–763
DOI: 10.1520/STP17908S
ISBN-EB: 978-0-8031-5187-1
ISBN-13: 978-0-8031-1477-7