Deformation and microstructure of neutron irradiated stainless steels with different stacking fault energy

The influence of the stacking fault energy (SFE) on the microstructure, mechanical property and deformation behaviour of stainless steels before and after irradiation was investigated. The mechanical properties, such as strength, ductility, strain hardening and irradiation induced hardening behaviours of 3 alloys with various SFEs are quite different. Such significant variations of mechanical properties must result from the different microstructures, deformation mechanisms and defects accumulation behaviours. Thus, the microstructures, deformation mechanisms and irradiation induced small defect clusters (including their types, natures, densities and size distributions) of 3 alloys are determined in detail by transmission electron microscopy. It indicated that before irradiation, alloy with low SFE has more localised deformation behaviour than alloy with high SFE. After irradiation, in the samples with low SFE, the irradiation induced stacking fault tetrahedral was observed, while in the ones with high SFE, the dominant defects are Frank loops. All the results shown that, SFE has a strong effect on both the deformation mechanism and irradiation induced defect accumulation behaviour of stainless steels.