Irradiation and thermal effects on the tensile properties of Inconel alloy 718

The effects of neutron irradiation and out-of-flux aging on the tensile properties of wrought and weld-deposited Inconel 718 were investigated following fast-reactor (EBR-II) irradiation to total fluences ranging from 0.55 x 1022 cm2 (approximately 4000C) to 6.6 x 1022 n/cm2 (6490C) and thermal exposure at 5380C and 6490C for durations to 10,000 hours. Classical irradiation hardening is exhibited by this very strong material following irradiation at low temperature (approximately 4000C) to relatively low fluence (approximately 1022 n/cm2) and also at high temperature when very high fluence (6.6 x 1022n/cm2) is accumulated. At test temperatures less that 5380C, ductility losses arising from helium embrittlement are evident for all irradiation conditions and at high fluences are so severe as to restrict the strength to lower than expected values. Low postirradiation strength, compared to that following out-of-flux aging for equivalent durations, suggests that irradiation accelerates the thermal overaging process at 5380C. At 6490C, the results are obscured by embrittlement and coincident limitations on strain hardenability. 8 fig