Recrystallization Nucleation in Some Channel Die Deformed, High Symmetry Aluminium Bicrystals

The crystallography of recrystallization nucleation in high purity aluminium bicrystals, with boundary planes situated parallel to the compression plane, has been characterized in detail by microtexture analyses. The experiments were carried out on samples with 2 types of bicrystal orientations composed of the stable Goss{110}<001> with an unstable cube{100}<001> or shear{100}<011> orientation. The bicrystals were cold deformed in channel-die compression up to true strains of 1.5. During recrystallization annealing, the deformation bands of the unstable orientations are the privileged sites for the formation of new grains. These nuclei were misoriented with respect to the orientations identified within the neighbouring deformed areas by α(<111>, <112> or <100>) relations. Growth of the new grains is always favoured along directions parallel to the traces of the {111} slip planes as shown in the stable and structurally homogeneous Goss {110}<001> oriented grains. The grain boundary can play a role in recrystallization similar to that of the deformation bands.