A study on commercial pure Al (1050) after cold rolling at room temperature with various deformations using positron annihilation

Positron annihilation lifetime (PAL), Doppler broadening (1313), and Vickers microhardness measurements (Hv) were performed to study the isochronal annealing of commercial pure Al (1050) in the temperature range from room temperature (RT) to 823 K after cold rolling at RT with various deformations of 16%, 37%, and 54%. PAL measurements show a decrease in the average lifetime of positron (tau(av)) followed by saturation at 190 ps as a function of annealing temperature. The results of Doppler broadening of annihilation radiation (S and W parameters) are found to be consistent with PAL measurements. The correlation between the characteristics of positron annihilation and Hv shows three annealing stages of microstructure in commercial Al, which are attributed to recovery, partial recrystallization, and complete recrystallization.