The Impact of Severe Plastic Deformation on the Microstructure and Physicomechanical Properties of Al–0.4Zr

Abstract

The influence of high pressure torsion on the microstructure and mechanical and electrical properties is elucidated for an Al–0.4Zr alloy pre-annealed at 648 K for 60 h. The transmission electron microscopy has revealed that the annealing causes the dispersive release of nanoparticles of a secondary Al₃Zr phase. The formation of this structure in the alloy ensures an increase in its conductivity from 50.7 to 58.8% IACS owing to a decrease in the Zr concentration in a solid solution. As established, high pressure torsion processing at room temperature of the pre-annealed alloy leads to the formation of a uniform ultrafine structure in them, as well as to the partial dissolution of Al₃Zr nanoparticles, resulting in higher strength and lower conductivity. It is shown that additional annealing of the ultrafine grained alloy for 1 h at 503 K results in a strength increase by 20% and the recovery of conductivity to the annealed state level (58.3% IACS).