Abstract
Effects of irradiation damage on the micro-crack initiation following the slip band formation and growth under low cycle fatigue in the proton-irradiated SUS316L austenitic stainless steel was investigated for improving the prediction method of the micro-crack initiation life under irradiation. The slip band spacing and the micro-crack initiation life of the specimen irradiated up to 0.25 dpa at 230℃ were about twice larger and one-fifth shorter than those of the unirradiated specimen, respectively. The micro-crack initiation in the unirradiated specimen occurred at the grain boundary, trans-crystalline, twin boundary and slip band. While, that occurred only at the twin boundary and slip band in the irradiated specimen. The number density of the slip band increased rapidly at the micro-crack initiation life ratio of 0.2〜0.4, and then it tended to saturate. These trends were independent of the irradiation.
