Particle redistribution and phase stability in ion and neutron irradiated gamma prime strengthened Fe-Cr-Ni based alloys

A series of Fe/15 wt% Cr/X wt% Ni γ'-strengthened alloys, with X ranging from 25 to 45 wt%, were systematically investigated in both nickel ion and neutron irradiation conditions. The major phases in this class of alloys in the austenitic matrix are spherical γ' particles and some blocky MC carbides (mostly TiC). At grain boundaries, M 6C, M 23C 6, Laves phase (for silicon-containing alloys) and cellular γ' were observed. In general, because of the enhanced point defect concentration under irradiation, enhanced growth kinetics of all these phases were observed. Solute redistribution and segregetion to dislocations and voids were also evident. Evidence of γ' dissolution was observed after exposure to both nickel ion and neutron irradiations. The γ' particle redistribution behavior after both nickel ion and neutron irradiations was analyzed quantitatively in terms of the Baron-Chang-Bleiberg theory.