Annealing Study of Dilute Aluminum Alloys Electron Irradiated at Liquid-Nitrogen Temperature

Abstract

Pure and dilute aluminum alloys (Mg, Zn, Ag, Ge, Au, and In) were irradiated at about 90 °K by 2- or 3-MeV electrons. Isothermal annealing for 30 min at temperature intervals 10 °C apart was carried out. The major results were the following: Stage-III annealing occurs by a second-order process with an activation energy $E_{\mathrm{III}}=0.60\mathrm{}\pm 0.04$ eV for both pure and dilute aluminum alloys. Since this activation energy is the same as that found by quenching experiments, it is concluded that stage III in aluminum and dilute aluminum alloys occurs by the motion of vacancies. Two stages below stage III are dependent on the kind of impurity. A mechanism consisting of a breakup of interstituals from impurity traps (single-impurity atoms or impurity-atom clusters) can explain the experimental results. Reverse recovery of electrical resistivity was observed below and above stage III; this is due to Guinier-Preston-zone formation.