Liquid helium quenching experiments on impure aluminium

Abstract

Liquid helium quenching and post-quench annealing experiments have been made on slightly impure Al. The energy of monovacancy formation, the apparent activation energies for Stage I annealing, and the temperature range for Stage I recovery are compatible with previously published data for pure Al. Simplified reaction schemes are discussed in an attempt to explain the annealing behaviour. Although the annealing models appear to describe observed kinetics and, in the divacancy case, give reasonable values for the vacancy/vacancy binding energy, they do not provide a full description of the annealing process. In particular, values of the apparent activation energy for Stage I decay obtained from cross-cut analyses of annealing isotherms are low in comparison with model predictions.