The residual resistivity of alloys with Ni contents between 42 and 71 at. % has been investigated during 3 MeV electron irradiation at 25 K, 82 K, and 95 K as well as during isochronal annealing up to 350 K. During irradiation at the given temperatures the resistivity increases probably due to point defect production. Significant resistivity recovery starts at about 90 K leading to total recovery at temperatures between 120 K and 200 K depending on alloy composition. At higher temperatures the resistivity decrease still proceeds causing strong negative resistivity changes being due to alloy decompositon. From the observed decomposition temperature it is concluded, that the required mass transport is due to interstitialcy migration.