Nucleation of recrystallised grains from cube bands in hot deformed commercial purity aluminium

The present work was initiated in order to obtain a better understanding of the nucleation mechanism of cube oriented grains during recrystallisation of hot deformed aluminium. Investigations included: the stability aspect of cube oriented grains during deformation, a characterisation of cube oriented areas in the as deformed condition, and partly recrystallised states. Commercial purity aluminium, plane strain compressed at various deformation conditions, was investigated mainly using the electron backscattering pattern (EBSP) technique in a scanning electron microscope (SEM). The following deformation and nucleation pattern was observed: cube oriented grains present in the starting material remain orientation metastable during deformation and are smeared out to bands. The cube bands have a unique subgrain size distribution with a long tail towards large subgrains, making them potent nucleation sites. The observed preferred nucleation from cube bands surrounded by the S deformation texture component, is discussed both in terms of a microgrowth selection mechanism and differences in stored energy between the cube and S oriented regions.

MST/3247