Positron studies of vacancy clustering in quenched aluminium and dilute aluminium alloys

Doppler broadening positron studies of annealing in quenched aluminium and dilute Al-Mg and Al-Zn alloys show that the effects of Mg and Zn on stage III annealing processes are essentially similar. Comparative analyses of the various measured annealing curves suggest that both microvoid and vacancy-loop formation are involved in stage III, the detailed balance being determined by the impurity concentration.