Effect of post-irradiation annealing on microstructure and corrosion of proton-irradiated 308L stainless steel weld metal

The effect of post-irradiation annealing (PIA) at 550 degrees C for 1 h on microstructure and corrosion of proton-irradiated 308L stainless steel weld metal was investigated. After PIA, growth of voids and Frank loops in austenite occurred, whereas Ni/Si-rich clusters in austenite, spinodal decomposition and G-phase in delta-ferrite, and segregation at grain boundary were removed. Corrosion experiments showed that the inner oxide thickness of austenite was increased by PIA, while the oxide scale on delta-ferrite was unaffected. In addition, localized corrosion was not observed along the grain boundary and carbide-free phase boundary, while it still remained along the carbide-containing phase boundary.