Abstract
Making annealing temperature-tensile strength and elongation curves of aluminum foils by a small tension tester and comparing with those of sheets of the same composition, we obtained the following results : (1) The increase of elongation after recrystallization of foils was lowered very much as compared with those of sheets. (2) The decrease of tensile strength of foils began from the early stage on annealing but the increase of elongation occurred only due to recrystallization. (3) There was no appreciable coarsening of crystals by annealing in foils thinner than 0.4 mm. As to their microstructure, the thinner the foils, the smaller the grain-size after recrystallization, but the diameter of the grain grew up to several times as large as the thickness. In thicker foils, deformation occurred uniformly over their all crystals, but as they become thinner, the numbers of deformed crystals decreased and even micro-cracks were observed. In the recrystallization texture of foils, by X-ray observation, there was no difference from the results of previous studies on aluminum rollings.
