Effect of isothermal annealing on the Bordoni relaxation in cold worked copper

Abstract

The Bordoni relaxation in ultra-purity cold worked copper subsequent to isothermal annealing in the temperature range 298-423 K at 700 Hz frequency is investigated using a set up based on the electrostatic system. The Bordoni peak is observed at 79 ___ 2 K. The annealing characteristics of the Bordoni peak are found to be of complex nature. The decay and subsequent regrowth of the peak following annealing above room temperature are interpreted in terms of defects diffusing to dislocations and their removal from dislocations, respectively. The calculated activation energy values for the first decrease (0.55 eV), first increase (0.24 eV) and first minimum (0.27 eV) are in good agreement with the activation energies for interstitial and di: vacancy diffusion estimated by different workers. The activation energy for divacancy diffusion is computed to be 0.49 eV.