Kinetics of interstitialcy diffusion in electron-irradiated Cu-Ni alloys

The residual electrical resistivity of an alloy Cu+58.7 at% Ni has been measured during 3 MeV electron irradiation at temperatures between 120K and 570K as well as during isothermal and isochronal annealing up to 570K. During isothermal irradiation the resistivity decreases due to decomposition of the alloy. For the temperature range 120-370K the observed decomposition kinetics are consistently interpreted by interstitialcy diffusion and a diffusion path of the three-dimensionally-migrating interstitials which is terminated by trapping and recombination reactions. The interstitials trapped during low-temperature irradiation are detrapped during 350K annealing. The reaction parameters obtained by a fit of the model calculations to the data amount to the same order of magnitude as the parameters found for pure Cu and dilute Cu alloys.