The grain size is moderately fine in the Al-Zr alloys containing Zr up to 0.3%, but is coarse in the alloys containing more of Zr. Restriction of grain growth or stabilization of grain size at elevated temperatures is achieved with increasing Zr content. Precipitation heat treatment is also effective for the purpose. Heating rates at about 350°C has a considerable effect on the recrystallized grain size, but those at temperatures up to about 250°C have little effect. Low temperature temper hardening has an unnoted effect on recrystallization. Hone and Pearson's electrolytic etching is effective to reveal the recrystallized grain structure in the Al-Zr alloys.