RADIATION-INDUCED SEGREGATION IN IRRADIATED TYPE-304 STAINLESS-STEELS

Grain boundary radiation-induced segregation (RIS) in two Type 304 stainless steels neutron-irradiated at 288-degrees-C has been investigated by analytical electron microscopy. In the conventional alloy (CP), narrow (less-than-or-equal-to 5 nm width) RIS zones depleted in chromium and iron and enriched in silicon, phosphorus, and nickel were observed near grain boundaries. For the higher purity alloy (HP), similar width (less-than-or-equal-to 6 nm) RIS zones depleted in chromium and enriched in nickel and iron were observed at boundaries, though at reduced magnitudes relative to those in the CP material. No significant segregation of silicon or phosphorus was observed in the HP material. RIS zones associated with faulted dislocation loops in the CP material were detected and shown to be depleted in chromium and enriched in nickel and iron relative to the matrix.