Cyclotron irradiation of Cu3Au alloys at low temperatures

Ordered and disordered Cu3Au alloys were irradiated at liquid nitrogen and helium temperatures with protons and α-particles from a cyclotron. An increase of resistivity by irradiation and its recovery by isochronal annealing were measured. The results were compared with those of copper irradiated and annealed under the same conditions. Defect introduction rates were carefully determined, based on which a resistivity due to Frenkel pairs in the alloy and a number of replacements in a cascade were estimated. The recovery of the order in the alloy occurred in the stage III and in the 4000K stage but not in the stage I and II, which suggests that the migrating defects in the former stages are vacancy families and those in the latter stages are interstitial families. It was shown that in the stage I annealing of the ordered alloy, the similar processes proceed as in the pure copper, while in the disordered alloy the long range migration of defects is prevented. It was also shown that the defects survived the stage I annealing in the disordered alloy disappear in the stage II