A study of the mechanism of loop growth in thin foils of an aluminium 3·0 at. % magnesium alloy using an energy analysing electron microscope

Parallel observations have been made of the plasmon energy losses and the growth of prismatic dislocation loops during annealing at 200°c of an aluminium 3·0 at. % magnesium alloy. It is shown that there is a continuous loss of magnesium during annealing and this supports the oxidation-vacancy emission loop growth mechanism suggested by Kritzinger, Dobson and Smallman (1967) to account for loop growth in aluminium-magnesium alloys. It is found that the rate of growth of loops varies by a factor of three from point to point within a given grain in the thin foil. This behaviour is explained in terms of local fluctuations in the efficiency of the oxide/metal interface for absorbing vacancies.