Characterization of aluminum processed by equal channel angular extrusion: Effect of processing route

Equal channel angular extrusion (ECAE) of aluminum alloys leads to enhanced strength. However, the effects of processing route on the resulting properties were not extensively investigated, and sometimes neglected. In the present work, an aluminum was processed by ECAE via routes BC and C using a die formed by two channels connected at an angle Ф = 90°. Coherency lengths D calculated from X-ray diffraction peaks were 85 nm after the first passage. For route BC, it was kept constant when the number of passages N was increased. For route C, an increase of D was observed when increasing N. The remaining densities of dislocations ρ were calculated using a recently published formula. A decrease of ρ was observed during ECAE in route C but not in route BC. Mechanical tests allowed us to relate the increase of D and the decrease of ρ to an enhanced recovery during ECAE via route C.