Abstract
Austenitic alloys are often observed to develop magnetic properties during irradiation, possibly associated with radiation-induced acceleration of the ferrite phase. Some of the parametric sensitivities of this phenomenon have been addressed using a series of alloys irradiated in the BOR-60 reactor at 593K. The rate of development of magnetic phase appears to be sensitive to alloy composition. To the first order, the largest sensitivities to accelerate ferrite formation, as explored in this experiment, are associated with silicon, carbon and manganese and chromium. Si, C, and Mn are thought to influence diffusion rates of point defects while Cr plays a prominent role in defining the chromium equivalent and therefore the amount of ferrite at equilibrium. Pre-irradiation cold working was found to accelerate ferrite formation, but it can play many roles including an effect on diffusion, but on the basis of these results the dominant role or roles of cold-work cannot be identified. Based on the data available, ferrite formation is most probably associated with diffusion.
