INFLUENCE OF HELIUM GENERATION RATE AND TEMPERATURE HISTORY ON MECHANICAL-PROPERTIES OF MODEL FE-CR-NI ALLOYS IRRADIATED IN FFTF AT RELATIVELY LOW DISPLACEMENT RATES

In agreement with earlier studies conducted at higher displacement rates, the evolution of mechanical properties at room temperature of model Fe-Cr-Ni alloys irradiated at lower displacement rates in the Ni-59 isotopic doping experiment does not appear to be strongly affected by large differences in helium generation rate. This insensitivity to helium/dpa ratio is exhibited during both isothermal and non-isothermal irradiation. The overall behavior of the model alloys used in this study is dominated by the tendency to converge to a saturation strength level that is independent of thermomechanical starting state and helium/dpa ratio, but which is dependent on irradiation temperature and alloy composition.