Deformation banding and grain boundaries in aluminum and aluminum alloys

Orientation imaging microscopy (OIM) methods have been employed to assess microstructures developed by deformation processing of pure aluminum and selected aluminum alloys. Grain maps constructed from orientation data illustrate the presence of deformation bands in which the lattice orientation alternates between the symmetric variants of the main texture component. Various shear texture components are observed in pure aluminum following equi-channel angular pressing, depending on the processing route. The B texture component {<112>{110}) is prominent in Supral 2004 following the final cold rolling stage of thermomechanical processing intended to enable superplasticity, while a C texture component (<111>{112}) is present following similar processing of a superplastic Al-5%Ca-5%Zn alloy. In all of these cases the high-angle {50 degrees -62.8 degrees) boundaries in the microstructure evolve from the interfaces between the bands while the lower-angle (2 degrees -15 degrees) boundaries separate cells within the bands. Models of microstructural development that include deformation banding during cold working may be employed to describe both texture development and the origin of the grain boundaries.