The mechanical properties of the ultrafine-grained (UFG) Al–1.5Cu (wt.%) alloy were investigated. The UFG structure was obtained using high pressure torsion (HPT) technique. UFG alloy demonstrates high values of microhardness (1690 MPa), yield strength (515 MPa) and ultimate tensile strength (655 MPa), but low ductility (~3%). Subsequent short-term annealing at 150 °C and additional HPT deformation to 0.25 rotations resulted in some decrease in ultimate tensile strength to 450 MPa, which was ~70% of the value before annealing but provided high ductility (~22%). The results suggests a high potential for practical application of the material. The proposed approach can be an universal effective way to achieve combination of high strength and high ductility for various UFG materials.

For the first time the influence of temperature of mechanical tension on the plastification effect (PE) in ultrafine-grained (UFG) Al-1.5Cu (wt.%) alloy was studied. The UFG structure in the material was formed by high pressure torsion (HPT). A significant increase in the plasticity (from ~ 3% to 22%) of the UFG alloy while maintaining high ultimate tensile strength (450 MPa) was achieved by additional treatment, including low temperature annealing and subsequent small additional HPT deformation. The temperature range of the PE implementation was revealed. It was shown that decrease of the deformation temperature leads to a gradual decrease of the PE and its disappearance at –20 oC. Cu alloying led to a significant narrowing of the range of PE implementation from low temperature side compared to the UFG commercially pure Al. Possible reasons of the influence of Cu alloying on temperature dependence of the PE are discussed.