Emulating neutron-induced void swelling in stainless steels using ion irradiation

Self-ion irradiation is currently being used to explore the relative void swelling resistance of various candidate advanced alloys for a wide variety of nuclear systems, including light water reactor (LWR) reactors. The credibility of using this surrogate irradiation technique to evaluate potential in-reactor behavior requires that certain facets of neutron-induced behavior be reproduced in the ion simulation. Of particular importance is the ability of ion irradiation to produce the anticipated post-transient swelling rates for fcc and bcc iron-base alloys characteristic of reactor irradiation at ~1.0%/dpa and ~0.2%/dpa, respectively. Using a model duplex Fe-9Cr-C alloy irradiated at 450 ℃ with 8 MeV Fe + ions it is shown in this study that a post-transient rate of ~0.2%/dpa is observed in the ferrite phase after an incubation period of ~60 dpa. It is also shown that the ferrite phase attains this rate first, while the tempered martensite phase exhibits a longer transient delay prior to the onset of high-rate swelling. © 2019, The Minerals, Metals & Materials Society.