Hardness and depth-dependent microstructure of ion-irradiated MgAl/sub 2/O/sub 4/
Stoichiometric polycrystalline magnesium aluminate spinel has been irradiated at 25 and 650/degree/C with 2.4 MeV Mg/sup plus/ ions to a fluence of 1.4 /times/ 10/sup 21/ ions/m/sup 2/ (/approximately/35 dpa peak damage level). Microindentation hardness measurements and transmission electron microscopy combined with energy dispersive X-ray spectroscopy measurements were used to characterize the irradiation effects. The room-temperature hardness of spinel increased by about 5% after irradiation at both temperatures. There was no evidence for amorphization at either irradiation temperature. Interstitial-type dislocations loops lying on /l brace/110/r brace/ and /l brace/111/r brace/ planes with <110> Burgers vectors were observed at intermediate depths (/approximately/1 ..mu..m) along the ion range. The <110>/l brace/111/r brace/ loops are presumably formed from <110>/l brace/111/r brace/ loops as a result of a shear on the anion sublattice. Only about 0.05% of the calculated displacements were visible in the form of loops, which indicates that spinel has a high resistance to aggregate damage accumulation. The peak damage region contained a high density of dislocations tangles. There was no evidence for the formation of voids or vacancy loops. The specimen irradiated at 650/degree/C was denuded of dislocation loops within /approximately/1 ..mu..m of the surface. 25 refs., 16 figs., 5 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 7020146
- Report Number(s):
- CONF-880613-14; ON: DE88012497
- Resource Relation:
- Conference: 14. international symposium on effects of radiation on materials, Andover, MA, USA, 27 Jun 1988; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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36 MATERIALS SCIENCE
MAGNESIUM OXIDES
MICROSTRUCTURE
SPINELS
RADIATION HARDENING
CERAMICS
IMPURITIES
IRRADIATION
SWELLING
TRANSMISSION ELECTRON MICROSCOPY
VOIDS
X-RAY SPECTROSCOPY
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
HARDENING
MAGNESIUM COMPOUNDS
MICROSCOPY
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL RADIATION EFFECTS
RADIATION EFFECTS
SPECTROSCOPY
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