Relationships between phase stability and void swelling in Fe-Cr-Ni alloys during irradiation

Austenitic Fe-Cr-Ni steels are potential candidate alloys for structural materials in both fast breeder and magnetic fusion reactors. However, void swelling and phase instability during irradiation have been major problems limiting the properties and useful lifetimes of these materials and thus have been the subject of intensive investigations. Cavity nucleation in steels subjected to displacement damage is strongly influenced by the interactions between helium atoms and precipitates which are formed during irradiation. Several important mechanisms regarding gas atom-precipitate interactions and principles for the design of radiation-resistant alloys are critically examined. Central concepts derived from theory, including the critical radius and critical number of gas atoms, cavity-precipitate interactions, and relative sink strengths for point defects, are applied to the interpretation of experimental data. This paper is based on a presentation made in the “G. Marshall Pound Memorial Symposium on the Kinetics of Phase Transformations” presented as part of the 1990 fall meeting of TMS, October 8–12, 1990, in Detroit, MI, under the auspices of the ASM/MSD Phase Transformations Committee.