Evolution of Dislocation Loops in AL-6XN Stainless Steels Irradiated by Hydrogen Ions

AL-6XN stainless steels, one of the candidate structure materials for supercritical water-cooled reactor, were irradiated from 0.5 to 5 dpa using 100 keV H2 + ions at 290 and 380 °C. Microstructures were characterized by transmission electron microscopy (TEM). Dislocation loops were the dominant radiation-induced defects. All the dislocation loops had 1/3 type Burgers vector. Number density and size of the loops have been measured. Nucleation and evolution of dislocation loops were also investigated. Voids were observed only in the condition of 5 dpa at 380 °C. Different evolution mechanisms of the radiation-induced dislocation loops were discussed. Effects of hydrogen and elevated temperature on the microstructural evolution were also investigated. Besides, the formed voids have a further effect on the evolution of dislocation loops.