Study on the Secondary Recrystallization of Al and Cu Foils

Abstract

It was described in the previous report that a secondary recrystallization occurred above a certain limit of reduction but did not occur bellow a certain limit of thicknes when Al and Cu foils were annealed. In this report foils with the same reduction and different thickness were annealed isothermally. The shape, the size and the orientation of the secondary recrystallized grains were observed. The results were as follows: (1) In Al, a secondary recrystallization occurred in the thicker foil (0.142 mm) but did not occur in the thinner foil (0.015 mm). (2) In the thicker Al foil some of the primary recrystallized grains, which were relatively large and had concave grain boundaries and special orientation, coarsened. (3) In the thinner Al foil such primary recrystallized grains were observed but a secondary recrystallization did not coccur. (4) In Cu foils the thinner the thickness, the larger the incubation period of the secondary recrystallization and the smaller the secondary recrystallized grains.