Study of decomposition of oversaturated solid solution in al–Sc–Zr alloys at different ratio of scandium and zirconium

Using electrical resistivity and hardness measurement methods and also electron microscopy analysis, the aging processes were studied in the Al-rich alloys of the Al–Sc–Zr system for contents of 0.1– 0.3% Sc and 0.04–0.28% Zr. A significant increase in the alloy hardness as compared with the quenched state was already established during aging at a temperature of 350°C after 1h. The character of the change in electrical resistivity and hardness during aging turned out to be similar for all studied alloys. However, the strengthening effect in the ternary Al–Sc–Zr alloys was higher than that in the binary Al–Sc alloys with the same Sc contents. Decomposition of the supersaturated Al solid solution was accompanied by precipitation of nanosize particles of the strengthening phases. © Pleiades Publishing, Ltd., 2011.