Response of solidification cellular structures in additively manufactured 316 stainless steel to heavy ion irradiation: an in situ study

ABSTRACT In-core or cladding structural materials exposed to heavy ion irradiation often suffer serious irradiation-induced damages. Introducing defect sinks can effectively mitigate irradiation-induced degradation in materials. Here, we investigated the radiation response of additively manufactured 316 austenitic stainless steel with high-density solidification cellular structures via in situ Kr++ irradiation at 400°C to 5？dpa. The study shows that the cellular walls with trapped dislocations can serve as effective defect sinks, thus reduce dislocation loop density compared with the conventional coarse-grained counterparts. This study provides a positive step for the potential applications of radiation-resistant, additively manufactured steels in advanced nuclear reactors. GRAPHICAL ABSTRACT IMPACT STATEMENT The solidification cellular walls with trapped dislocations in additively manufactured 316 SS can serve as effective defect sinks that prominently reduce irradiation-induced defect density compared with the conventional coarse-grained counterparts