Theoretical1,2as well as experimental observations3suggest that irradiation may alter the volume fraction of precipitate present in a two-phase alloy. Particularly appropriate to the present work, Korenko3has irradiated an Ni-7.1 wt.% Al alloy at temperatures between 450 and 750°C using 1.0-MeV electrons in the high-voltage electron microscope (HVEM). Irradiation to doses of ∼7 displacements per atom (dpa) and temperatures near 600°C reportedly revealed drastic increases in the volume fraction of γ′, i.e., from 10 to 100% (pure γ′). The present results are consistent with Korenko's experimental observations except that the volume fraction of γ′ in the foil is not significantly altered by irradiation.