Orientation of recrystallized grains in strained aluminum single crystals

Abstract

Artificially nucleated crystals were grown in strained aluminum single crystals by cutting them at one end with pliers and then subjecting them to recrystallization heating. An overwhelming majority of the new crystals showed an orientation characterized by a 40° rotation around the [11̄1] axis relative to the old matrix. Recrystallization always started at the cut end with many fine grains. After further heating most of these fine grains disappeared and only a few large crystals were left. They grew further into the deformed matrix and one of them finally occupied the full diameter of the wire. Laue and Debye-Scherrer X-ray photographs showed that in the early stage of recrystallization the orientation of the many fine grains were distributed at random, while the crystal finally obtained usually was characterized by a 40° [11̄1] rotation. This indicates that the preferred orientation of the final crystals originates in growth selection. The preference for [11̄1] rather than the other 〈111〉 axes may be caused either by the plastic deformation of the old matrix, or by the fact that the boundary between the two crystals is a pure tilt boundary if both have a common [11̄1] axis.