Nickel-ion bombardment studies were conducted on experimental alloys which were designed to provide basic information on the influence of composition, residual elements, and γ'-precipitates on swelling in the iron-chromium-nickel alloy system. Bombardments were conducted at temperatures ranging from 550 to 750°C (1022 to 1382°F) to maximum damage of 250 displacements per atom (dpa).

Comparison of identical alloys with and without γ'-precipitates showed that titanium and aluminum additions to the matrix compositions suppressed swelling. It is inferred that the aluminum increases the incubation dose while titanium reduces the swelling rate. The γ'-precipitates influence swelling only as they affect matrix chemistry.

Fine γ'-particles (8 to 18 nm) were precipitated under irradiation and approached an equilibrium size at high damage levels. A slight coarsening of 30-nm particles was observed, but there was only a slight increase in the volume fraction of the γ'-particles due to the irradiation. It was concluded that disorder dissolution was not an important mechanism in these alloys.