Isochronal annealing of vacancies in aluminium

Abstract

A study based on electrical resistivity measurements at liquid nitrogen temperature has been carried out on the isochronal annealing out of quenchedin vacancies in 99.995% Al. The procase of annealing takes place in two stages; the first stage is centred at about room temperature and takes place at a lower temperature the higher the quenching temperature; also the observed migration energies (in the range 0.37 to 0.58ev) and the mean number of jumps for annihilation (in the range 10⁴ to 10⁹) are very sensitive to the initial concentration of defects, that is to the quenching temperature. The second stage takes place at about 160°c and its amount increases largely with quenching temperature; its activation energy results in 1.3±0.2 ev. The results have been interpreted as due principally to a clustering of vacancies (first stage) and subsequent dispersion of clusters by self-diffusion (second stage).