Role of Low-Level Void Swelling on Plasticity and Failure in a 33 Dpa Neutron-Irradiated 304 Stainless Steel

Radiation damage introduces a wide range of defects in structural materials depending on the irradiation conditions. Irradiation-induced loops are known to lead to dislocation-channeling, which reduces the work hardenability and increases the susceptibility to intergranular stress corrosion cracking. In a higher temperature regime, void formation is an integral radiation -induced defect type in addition to radiation-induced loops. Previous bulk mechanical tests sug-gest that a high level of void swelling can lead to severe embrittlement while a low level of void swelling does not negatively affect intergranular cracking and ductility. This study utilized microscale bicrystal testing to evaluate the role of low-level void swelling on dislocation-channel suppression and intergranular cracking in a 33 dpa neutron-irradiated 304 stainless steels with 2% and 3.7% void swelling. The results provided direct observation on the suppression of dislocation-channel and intergranular cracking in the presence of low-level void swelling.