On the origin of the R orientation in the recrystallization textures of aluminum alloys

The crystallographic textures of most Al alloys, after rolling and recrystallization, are composed of two components, the cube orientation {001}[100] and a component similar to the former rolling texture, the so-called R orientation {124}[211]. The R orientation can be retained from the rolling texture in cases where the stored dislocation energy is being reduced merely through extended recovery reactions, which is referred to as continuous recrystallization. In addition, R-oriented grains can form through genuine, discontinuous recrystallization by nucleation within S-oriented grains at the grain boundaries between the deformed bands and a subsequent growth selection as caused by orientation pinning. The strength of the R orientation in the recrystallization textures strongly depends on the pretreatment and processing parameters of the material and, in particular, on the alloy investigated. The present article gives a survey of the factors affecting the R orientation and reviews recent results on the formation mechanisms of this orientation, which have been obtained by local texture analysis. The results are discussed with regard to the competition of the Ii orientation with the cube orientation during the evolution of the recrystallization textures in Al alloys.