Commercially AA1070 aluminium was processed by micro/mesoscale equal channel angular pressing (ECAP) up to four passes, via route [Formula: see text], to achieve fine grain structure and thereby enhancing the mechanical properties. Subsequently, the samples subjected to ECAP processing underwent an extrusion deformation in micro/mesoscale. The microstructural evolution of the deformed structures was followed using electron backscatter diffraction. The findings confirm that a remarkable refinement in the grain structure was observed as a result of the gradual transformation of the low angle grain boundaries into high angle grain boundaries through the grain subdivision mechanism. Consequently, a substantial improvement of the mechanical properties of the extruded material is promoted compared to the samples subjected to ECAP processing.