Effect of rolling temperature and subsequent annealing on electrical conductivity and strength of an aluminum alloy

An aluminum alloy Al–1% Fe–0.25% Si–0.3% Zr was chosen for the study. The alloy was rolled at the temperatures of 300 and 400°C and then annealed at 400°C for 3 hours. Rolling resulted in an increase in the strength of alloy. Subsequent annealing led to decomposition of the solid solution and the forming of Al3Zr (L12) particles with an average size of 5 nm. Decomposition of the solid solution was accompanied by an increase in the electrical conductivity from 46% IACS of cast alloy to 55% IACS. Rolling at 400°C with subsequent annealing strengthened the alloy. This was attributed to the precipitation strengthening and a little decrease of dislocation strengthening. In contrast, rolling at 300°C followed by annealing softened the alloy due to a decrease in the strengthening contributions from dislocations and precipitations.