Microstructural Defects in SiC Neutron Irradiated at Very High Temperatures
- ORNL
Microstructures in high purity ESiC irradiated with fast neutrons (up to ~9.6 1025 n/m2, in HFIR) at very high temperatures (1130, 1280, and 1460 C) were studied by transmission electron microscopy. Cavities and dislocation loops were generally observed in irradiated samples. The cavities were preferentially formed at grown-in stacking faults, and were spherical in shape below 1280 C and mainly faceted with {111} planes at 1460 C. Estimated volume fractions of observed cavities were much smaller than macroscopic densitometer swelling recently reported, which implies other defects cause the swelling in this temperature regime. Larger Frank loops (>25 nm in radius) formed at 1460 C were identified as interstitial type using the inside/outside method. Unfaulting of the loops was not observed or was very rare. Rapid loop growth and density decrease were observed in the temperature range of 1280-1460 C concurrently with the rapid cavity growth. The limited growth rate of dense loops at lower temperature was discussed in terms of high sink strength estimated from a grain-boundary-loop-denuded zone formed at 1130 C.
- Research Organization:
- Oak Ridge National Laboratory (ORNL); High Flux Isotope Reactor; Shared Research Equipment Collaborative Research Center
- Sponsoring Organization:
- NE USDOE - Office of Nuclear Energy
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 943532
- Country of Publication:
- United States
- Language:
- English
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