ISSN: 1546-962X
CODEN: JAIOAD
Published Online: 7 April 2004
Page Count: 15

Mechanical and Structural Property Changes of Monolithic SiC and Advanced SiC/SiC Composites due to Low Temperature He⁺-Ion Irradiation and Post-Irradiation High Temperature Annealing

Nogami, S
Graduate student, Graduate student, Associate Professor, and Professor, Tohoku University, Sendai,

Miwa, S
Graduate student, Graduate student, Associate Professor, and Professor, Tohoku University, Sendai,

Hasegawa, A
Graduate student, Graduate student, Associate Professor, and Professor, Tohoku University, Sendai,

Abe, K
Graduate student, Graduate student, Associate Professor, and Professor, Tohoku University, Sendai,

(Received 8 July 2002; accepted 17 April 2003)

Abstract

The hardness and elastic modulus of monolithic β-SiC and advanced SiC/SiC composites irradiated to He-concentrations of from 1000 to 20 000 at.ppm at a temperature below 100°C were investigated. Changes in the hardness and elastic modulus were correlated with He release behavior and with irradiation-induced microstructural changes and swelling. The hardness and elastic modulus of the irradiated specimens decreased with He concentration. Amorphized regions were observed in the He-irradiated monolithic β-SiC. The mechanical property changes likely were due to irradiation-induced amorphization. By the annealing at 1200°C, nearly full recovery was achieved. He release peaks from the pyrolitic graphite, monolithic SiC, and the SiC/SiC composites at 250, 700, 1000, and 1150°C, were identified. The correlation between the mechanical property and microstructural changes and the He release behavior are discussed.

Keywords:
SiC/SiC composite, helium, ion irradiation, nano-indentation, microstructure, thermal desorption

Paper ID: JAI11335
DOI: 10.1520/JAI11335
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