Cyclic fatigue of near-isotopic graphite: influence of stress cycle and neutron irradiation

Technical Report · Tue Nov 01 04:00:00 EST 1977

DOI:https://doi.org/10.2172/6550589· OSTI ID:6550589

Price, R J

Near-isotropic graphites H-451 and PGX were tested in uniaxial cyclic fatigue, and fatigue life (S-N) curves were generated to a maximum of 10/sup 5/ cycles. The stress ratio, R (minimum stress during a cycle divided by maximum stress) ranged from -1 to +0.5. With R = /sup -/1, the homologous stress limits (maximum applied fatigue stress divided by the tensile strength) for 50% specimen survival to 10/sup 5/ cycles averaged 0.63 in the axial direction and 0.74 in the radial direction. Corresponding homologous stress limits for 99% specimen survival (99/95 tolerance limits) were 0.48 and 0.53. Higher R-values resulted in longer fatigue lives and increased stress limits. H-451 graphite specimens irradiated with fast neutrons at 1173 to 1263/sup 0/K at fluences of up to 10/sup 26/ n/m/sup 2/ (equivalent fission fluence) showed fatigue stress limits of about twice the unirradiated levels when the unirradiated tensile strength was used as the basis for normalization.

• Research Organization: General Atomic Co., San Diego, CA (USA)
• DOE Contract Number: EY-76-C-03-0167-017
• OSTI ID: 6550589
• Report Number(s): GA-A-14588
• Country of Publication: United States
• Language: English

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CARBON
ELEMENTS
FAILURES
FATIGUE
GAS COOLED REACTORS
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GRAPHITE MODERATED REACTORS
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