Interaction of Precipitation and Recrystallization in Cold-Rolled Al–Er and Al–Er–Zr Alloys

The interaction of precipitation and recrystallization in the cold rolled Al–Er and Al–Er–Zr alloys was investigated. The results indicate that homogeneous precipitation of Al3Er starts before recrystallization in Al–Er alloy. Precipitation formed before the recrystallization leads to precipitation hardening in early stage of annealing. At the same time it also retards recrystallization. The kinetics of homogeneous precipitation in Al–Er–Zr alloy is sluggish compared to that in the Al–Er alloy, but the formation of heterogeneous nucleated precipitation on subgrain boundaries and dislocations prevents recrystallization. The effect of heterogeneous precipitation on hardness increase is not greater than that of recovery/recrystallization on hardness decrease during early stage of annealing, so there’s no significant increase in hardness for cold-rolled Al–Er–Zr alloy.