Dislocation loops formed by quenching thin aluminium specimens in iced brine -were studied by the transmission electron microscope technique. As-quenched specimens contained loops 200 Å to 600 Å in diameter with a density of 1016loops per cubic centimetre. Quenched-in loops were completely removed by heating to 200°c for ten minutes or by cold rolling to a 5% reduction in thickness. The disappearance of the loops was accompanied by an increase in the number of irregular kinked dislocation lines.