The deformed microstructure in 316 stainless steel (316SS), after neutron irradiation at 65 to 100C to 0.78dpa, was investigated by transmission electron microscopy. Deformation-induced martensite transformation and dislocation channelling were observed at irradiation dose higher than 0.1dpa. Estimation of the resolved shear stress (RSS) associated with each dislocation channel indicated a tendency for the RSS and channel width to be greatest when the angle between tensile axis and slip plane normal was around 45°. Furthermore, channel width increased with increasing RSS, indicating that the most extensive localized channel deformation tends to occur at a high RSS level. Deformation-induced martensite phase was found at various strain levels even at room temperature and tends to be exhibited mainly at intersections of channels. This suggested that a very high stress could lead to the γ→α martensite formation by the spreading of a Shockley partial dislocation over successive <111>fcc planes.

Deformation-Induced Martensite Formation and Dislocation Channeling in Neutron-Irradiated 316 Stainless Steel. N.Hashimoto, T.S.Byun: Journal of Nuclear Materials, 2007, 367-370[2], 960-5