Irradiation-altered precipitation in Fe-Ni-C alloys

Abstract A brief outline of the theory of the chemical vacancy effect and its application to the problem of irradiation-altered precipitation in Fe-Ni-C alloys is presented. A numerical evaluation of the magnitude of the chemical vacancy effect indicates that at a displacement rate of 10 −3 dpa/s, it might be possible to induce graphite precipitation in alloys of Fe-35%Ni which are undersaturated in carbon. Ion bombardment of Fe-35% Ni-0.03 wt% C, Ni-0.007 wt% C, and Ni-0.08 wt% C at approximately 600°C and 3 × 10 −3 dpa/s, however, produces no indication of graphite or carbide precipitation. However, thermal ageing induces graphite precipitation in the thermally supersaturated Ni-0.08 wt% C alloy. Possible reasons for the irradiation stability of these alloys are discussed.