The effects of residual stress on corrosion behavior of ion irradiated type 316L stainless steel

The effect of residual stress on corrosion behavior in type 316L austenitic stainless steel was examined by ion irradiated specimens. Ion irradiation was performed by 12 MeV Ni-ion at temperature from 330 to 550oC to average displacement damage levels from 1 to 45 dpa. During irradiation, residual stress was applied on the specimen by plastically bending deformation constraint. Specimens without the bending deformation constraint were also irradiated simultaneously. Corrosion behaviors of these irradiated specimens were estimated by means of SL-EPR testing. It was observed that the effects of residual stress on corrosion behavior were dependent on the irradiation dose and temperature. In order to examine the effects on microstructure and microchemistry, TEM and the three-dimensional atom probe (3DAP) analysis was conducted on the 6 dpa irradiated specimens. It was found that the enrichment of Ni, Si and the depletion of Cr at dislocations and dislocation loops and the degree of enrichment and depletion of these solute atoms was affected by residual stress. It was considered the corrosion behavior was related to the diffusion behavior of the solute atoms that was influenced by the residual stress. (author)