Effects of Thermal Annealing on the Macroscopic Dimension and Lattice Parameter of Heavily Neutron-Irradiated Silicon Carbide

Hiroyuki Miyazaki, Tetsuya Suzuki, Toyohiko Yano, Takayoshi Iseki

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Reaction-sintered (β-SiC specimens were neutron-irradiated in fast breeder reactors to fluences from 3.0×1024 to 1.7×1027 n/m2 (E>0.1 MeV) at temperatures from 370 to 620°C. Irradiation to fluences above 4.8×1026 n/m2 caused swelling (growth) that was significantly greater in respect of macroscopic dimension than of lattice parameter. These highly irradiated specimens also showed significant broadening of their X-ray line profiles, accompanied by generation of interstitial dislocation loops. Upon annealing, all specimens, irrespectively of the fluence to which they had been irradiated, tended toward recovery of their swelled macroscopic dimension and lattice parameter. This tendency was initiated when the annealing temperature exceeded that of irradiation, with the percentage of residual swelling lowering roughly in proportion to annealing temperature. The more highly irradiated specimens, in which the macroscopic dimension had swelled significantly more than the lattice parameter, lowered their percentages of residual swelling while maintaining a constant difference between them, as the annealing temperature was raised from that of irradiation to 1,200°C. In a certain range of higher annealing temperatures, the lattice parameter fell below the pre-irradiation level. In the range below 1,200°C, the broadened X-ray line profile indicated no tendency to recover. Microstruc-tural observations have indicated that the size and the number density of dislocation loops remain unchanged up to 1,000°C. The recovery of swelled macroscopic dimension and lattice parameter by annealing is discussed in terms of the recombination of point defects, which occurs even in the specimens irradiated to 1.7×l027n/m2 fluence.

Original languageEnglish
Pages (from-to)656-663
Number of pages8
JournalJournal of Nuclear Science and Technology
Volume29
Issue number7
DOIs
Publication statusPublished - 1992
Externally publishedYes

Fingerprint

Silicon carbide
silicon carbides
Lattice constants
lattice parameters
Neutrons
Annealing
neutrons
annealing
fluence
Irradiation
swelling
Swelling
irradiation
tendencies
Temperature
recovery
temperature
breeder reactors
Recovery
X rays

Keywords

  • dislocation loop
  • irradiation temperature
  • lattice parameter
  • macroscopic dimension
  • neutron irradiation
  • point defects
  • radiation doses
  • silicon carbide
  • thermal annealing
  • X-ray diffraction
  • X-ray line broadening

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Nuclear Energy and Engineering

Cite this

Effects of Thermal Annealing on the Macroscopic Dimension and Lattice Parameter of Heavily Neutron-Irradiated Silicon Carbide. / Miyazaki, Hiroyuki; Suzuki, Tetsuya; Yano, Toyohiko; Iseki, Takayoshi.

In: Journal of Nuclear Science and Technology, Vol. 29, No. 7, 1992, p. 656-663.

Research output: Contribution to journalArticle

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