Anisotropic dislocation loop nucleation in ion-irradiated MgAl sub 2 O sub 4
Polycrystalline disks of stoichiometric magnesium aluminate spinel (MgAl{sub 2}O{sub 4}) were irradiated with 2 MeV Al{sup +} ions at 650{degrees}C and subsequently analyzed in cross-section using transmission electron microscopy (TEM). Interstitial dislocation loops were observed on 110 and 11 habit planes. The population of loops on both sets of habit planes was strongly dependent on their orientation with respect to the ion beam direction. The density of loops with habit plane normals nearly perpendicular to the ion beam direction much higher than loops with habit plane normals nearly parallel to the ion beam direction. On the other hand, the loop size was nearly independent of habit plane orientation. This anisotropic loop nucleation does not occur in ion-irradiated metals such as copper. An additional anomaly associated with ion-irradiated spinel is that the loops on 111 planes were partially unfaulted with a Burgers vector of b = a/4<110>. Previous neutron irradiation studies have never reported unfaulted loops in stoichiometric spinel. Possible cause of the unusual response of spinel to ion irradiation are discussed. 12 refs., 14 figs.
- Research Organization:
- Oak Ridge National Lab., TN (United States)
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5147593
- Report Number(s):
- CONF-911111-2; ON: DE92001681
- Resource Relation:
- Conference: International conference on fusion reactor materials, Clearwater, FL (United States), 17-22 Nov 1991
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
ALUMINIUM OXIDES
ION IMPLANTATION
PHYSICAL RADIATION EFFECTS
MAGNESIUM COMPOUNDS
THERMONUCLEAR REACTOR MATERIALS
CERAMICS
CROSS SECTIONS
DISLOCATIONS
MICROSTRUCTURE
NUCLEATION
TRANSMISSION ELECTRON MICROSCOPY
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
LINE DEFECTS
MATERIALS
MICROSCOPY
OXIDES
OXYGEN COMPOUNDS
RADIATION EFFECTS
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