Characterization of deformation structure in ion-irradiated stainless steels

The effects of strain rate and type of stainless steels on the deformation behavior of irradiated stainless steels were investigated. Type 316 and 304 stainless steels irradiated with 200 keV He+ ions up to 20 dpa at 300 °C were deformed at 10−4 and 10−7/s at 300 °C. The deformation changed from uniform dislocation tangling to dislocation channeling and twinning, and slip step spacing widened due to prevention of dislocation gliding by dislocation loops and cavities. The deformation mode was the same in both stainless steels deformed at both strain rates. The loop and cavity density in type 304 stainless steel was smaller than that in type 316 stainless steel. However, dislocation gliding was more effectively prevented in the case of faster deformation and in type 304 stainless steel when dislocation loops were the dominant microstructure. The difference became small at higher doses when cavities were the dominant microstructure.