Microstructural evolution study of severely deformed commercial aluminium by transmission Kikuchi diffraction

Abstract

Commercially pure aluminium was selected as a model fcc material for a detailed investigation of the microstructural and textural evolution during processing by high pressure torsion (HPT). Vickers hardness measurements reveal that: the hardness is the lowest where the lowest strain is imposed and increases with increasing strain until saturation hardness is obtained. The microstructural evolution is investigated by means of electron backscattered diffraction and transmission Kikuchi diffraction. During HPT a grain fragmentation process takes place: within the original grains dislocations aggregate, resulting in the creation of very fine grains separated first by low and later by high angle grain boundaries. At a strain level of (Formula presented.) a simple shear texture of fcc structure was observed.