Joint effect of scandium,chromium, and zirconium on the aging and recrystallization of aluminum alloys

Metallography and electrical resistivity and hardness measurements are used to study the aging and recrystallization of Al-rich Al-Sc-Cr-Zr alloys with 0.1–0.4% Sc, 1.0% Cr, and 0.2% Zr. During aging at 350°C, the hardness of the alloys is found to increase substantially even after 0.5-h aging as compared to that of the deformed state. Variations of the hardness and electrical resistivity of all alloys exhibit similar behavior; however, the higher the scandium content in the alloys, the higher the strengthening effect reached after aging for 2–4 h. Combined small scandium, chromium, and zirconium additions to aluminum are shown to increase its recrystallization temperature; therewith, the effect of scandium on the increase in the temperatures of the onset and finish of recrystallization is more substantial.