On the recovery of quenched and irradiated dilute Al-Li alloys

Abstract

The annealing spectra of quenched and irradiated pure Al and dilute Al‐Li alloys containing 2.5 and 4.5 at% Li are isochronally tested in the temperature range 25 to 400 °C, by using both resistivity and internal friction measurements. The annealing spectrum of pure Al involves two recovery processes centred near room temperature and 160 °C. The first process is inferred to the coagulation of vacancies to form vacancy platelets and its subsequent collapse to give dislocation loops. The second process is attributed to the subsequent growth of the dislocation loops by dislocation climb. The annealing spectra of the quenched dilute Al‐Li alloys, shows three internal friction peaks in the temperature ranges 25 to 120, 120 to 200, and 200 to 300°C, characterized by activation energies 0.7, 1.3, and 1.44 eV, respectively. The first annealing band is ascribed to the annealing of vacancy‐Li couples formed during the quenching with the possible formation of GP zones. The second band is attributed to lithium atom dispersion. by normal diffusion from aggregates. The third annealing stage is thought to be due to the tendency of solute atoms to cluster in the matrix in the form of (AlLi) particles.