Neutron-irradiation damage in ceramic solids

Thesis/Dissertation · Fri Jan 01 00:00:00 EST 1982

OSTI ID:6494449

Youngman, R A

The neutron-irradiation damage structures of four ceramic solids irradiated in the EBR-II Fast Breeder Reactor to doses of approx. =10/sup 26/ n/m/sup 2/ at temperatures of 925 K and 1100 K have been investigated via transmission electron microscopy. The damage structure of ..cap alpha..-Al/sub 2/O/sub 3/ single crystals and polycrystals consists of a high density dislocation structure containing predominantly anti b = 1/3 <1011> dislocation loops on (0001) planes and a high density of voids which are aligned along the c-axis. Evidence for silicon impurity segregation to void surfaces is apparent. Irradiation of both single crystal and polycrystalline MgAl/sub 2/O/sub 4/ produces faulted interstitial Frank dislocation loops of anti b = 1/4<110> lying on (110) planes. Much smaller loops of anti b = 1/6<111> lying on (111) planes are also present in single crystals irradiated at 925 K. The irradiation-produced microstructure of ..beta..-Si/sub 3/N/sub 4/ contains two types of damage; a high density of faulted planar defects on the (1010) planes and similar faulted, interstitial, dislocation loops of anti b approx. = 1/10<1125> form on the (1010) planes. The faulted loops form from an apparent dissociation of two arcs of the helices with a Burgers vector of b approx. = 1/10<1125>. A very low density of faulted defects lying on (110) planes form in single crystal Y/sub 3/Al/sub 5/O/sub 12/ irradiated at 1100 K, whereas no defects form in the polycrystalline material or in samples irradiated at 925 K. There is no microstructural evidence for any other irradiation-induced damage.

• Research Organization: Case Western Reserve Univ., Cleveland, OH (USA)
• OSTI ID: 6494449
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM OXIDES
PHYSICAL RADIATION EFFECTS
ALUMINATES
MAGNESIUM COMPOUNDS
SILICON NITRIDES
YTTRIUM COMPOUNDS
ALUMINIUM COMPOUNDS
DEFECTS
DISLOCATIONS
MONOCRYSTALS
NEUTRONS
ALKALINE EARTH METAL COMPOUNDS
BARYONS
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
LINE DEFECTS
NITRIDES
NITROGEN COMPOUNDS
NUCLEONS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
RADIATION EFFECTS
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360206* - Ceramics
Cermets
&amp; Refractories- Radiation Effects