Abstract
Effects of additions of yttrium 0.04 to 0.2% and a commercially available unseparated mixture of yttrium group on the recrystallization temperature of Al-Zr alloys containing 0.1 to 0.3%Zr were examined. Minor additions of yttrium and mixture of yttrium group to the Al-Zr alloys have a considerable effect to elevate the recrystallization temperature. The effect is intensified by precipitation treatment. It is the most remarkable in the Al-Zr alloy containing about 0.2%Zr, but is not so remarkable in the dilute alloys such as Al-0.1%Zr alloy. Such an effect of yttrium and its group is explained by an enhancement of precipitation of finely dispersed Al3Zr particles during the precipitation treatment of Al-Zr supersaturated solid solution.
