Experiments in high voltage electron microscopy. Progress report, October 31, 1978-August 1979
High voltage electron microscopy (HVEM) has been used to study radiation damage in metals and ceramics, along with supplemental investigations using neutron and ion irradiation. Studies of alloys have concentrated on radiation effects on phase stability, particularly precipitate growth and, most recently, order/disorder transitions. ..beta..-phase alloys (e.g., FeAl) disorder under irradiation, but also develop unique striated structures with streaks in the diffraction patterns (especially NiAl), which may be due to secondary defects or a second phase. In simple oxides such as MgO, Arrhenius plots of dislocation loop growth rates give a high temperature activation energy corresponding to vacancy migration and an apparent low temperature activation energy corresponding to interstitial migration. Both electron and neutron irradiation produce voids in Al/sub 2/O/sub 3/; in addition neutron-irradiated polycrystalline Al/sub 2/O/sub 3/ exhibits microcracking along grain-boundaries due to aisotropic swelling. Further studies of the radiation-induced metamictization of quartz have revealed that the strain centers which are observed prior to the general amorphization are probably amorphous inclusions; these inclusons are much more prominent in wet synthetic quartz than dry lunar quartz. Ceramics with more complex crystal structures are much more resistant to the formation of interstitial loops and voids (and hence swelling) under both electron and neutron irradiations.
- Research Organization:
- Case Western Reserve Univ., Cleveland, OH (USA). Dept. of Metallurgy and Materials Science
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- EY-76-S-02-2119
- OSTI ID:
- 5880184
- Report Number(s):
- COO-2119-22
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360106* -- Metals & Alloys-- Radiation Effects
360206 -- Ceramics
Cermets
& Refractories-- Radiation Effects
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
ALUMINIUM ALLOYS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CHALCOGENIDES
ELECTRON MICROSCOPY
IRON ALLOYS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MICROSCOPY
NICKEL ALLOYS
ORDER-DISORDER TRANSFORMATIONS
OXIDES
OXYGEN COMPOUNDS
PHASE STUDIES
PHASE TRANSFORMATIONS
PHYSICAL RADIATION EFFECTS
QUARTZ
RADIATION EFFECTS
SILICON COMPOUNDS
SILICON OXIDES
SWELLING
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES