The deformation and work hardening behaviour of a SPD processed Al-5Cu alloy

An Al-5 wt.% Cu alloy supersaturated with Cu in solid solution was subjected to equal channel angular pressing (ECAP). The microstructural evolution was systematically investigated by backscattered electron (BSE) imaging, electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It is revealed that a bimodal grain structure composed of coarse micron-sized grains and submicron-sized grains was developed after four passes of ECAP. Tensile testing showed that a high ultimate tensile strength of ∼500 MPa, a high elongation to failure of ∼28% and a uniform elongation of ∼5% were achieved simultaneously. The deformation behaviour and the grain structure evolution during ECAP, the strengthening mechanisms of the as-deformed material, and especially, the role played by a high content of Cu have been discussed.