Electron irradiation of Cu3Au

Ordered and disordered Cu3Au were irradiated with 1 MeV and 1.5 MeV electrons at low temperature, and subsequent isochronal annealings were obtained at different pulse times from 30°K to 450°K. The initial resistivity increase per incident electron for the ordered specimens was about one-half that for the disordered specimens, suggesting that no significant radiation disordering takes place in the ordered polycrystalline samples. Irradiation with 1 MeV electrons of disordered specimens induces four annealing stages at the approximate temperatures of 90°K, 130°K, 330°K and 410°K. A disordered specimen, following irradiation with 1.5 MeV electrons, exhibits all four of these stages and, in addition, two more at 55°K and 190°K. These latter stages are attributed to the annealing of Au interstitials because 1.5 MeV is a sufficient electron energy to produce them but 1 MeV is not. In contrast, the ordered Cu3Au exhibits only three stages, at 75°K, 240°K and 410°K, for both 1 MeV and 1.5 MeV irradiations. It is proposed that focusons dissipate the energy in the ordered specimens so that Au interstitials cannot form. Tentative defect assignments are given to all stages.