MIGRATION PROPERTIES OF VACANCIES AND THEIR INFLUENCE ON THE ENHANCED ATOMIC MOBILITY IN ALPHA-BRASS EXPOSED TO ELECTRON-IRRADIATION

Radiation enhancement of directional order has been studied in a α-Cu 30 at.% Zn alloy, by anelasticity measurements during electron irradiation in the temperature range between 50 and 170°C. It is shown that a steady state is established after short irradiation periods. The corresponding activation energy is found to be 0.37 ± 0.02 eV, which implies a migration energy of 0.74 ± 0.04 eV for the vacancies. This value is compared with those derived from the study of thermal vacancies in equilibrium or the quenched state. Implications of these results for the mobility of the self-interstitials are discussed. In addition, previous resistivity measurements of the short range ordering rate in the same range of irradiation temperatures are reinterpreted in the light of the present findings. © 1979.