Analysis of Orientation Relations Between Deformed Grains and Recrystallization Nuclei

Nucleation in 30 pct rolled high-purity aluminum samples was investigated by the electron backscattering pattern method before and after annealing. A total of 29 nuclei including two twins were observed, and approximately one third of these nuclei had orientations not detected in the deformed state. Possible orientation relations between these nuclei and the deformed state were by 20 to 55 deg rotation around axes. These axes were compared with the active slip systems, and the crystallographic features of the deformation-induced dislocation boundaries. Good agreement was found between the rotation axes and the normal to slip planes with which dislocation boundaries align. The exact nucleation mechanism has not been established, but the observed orientation relations allow for prediction of which grains are likely to form rotated nuclei, although these may not all do so.