Abstract:The influence of trace Er addition on high pure aluminum was studied by mechanical properties measurement，hardness measurement, optical microscope，transmission electron microscope and energy spectrum analysis. The results show that minor Er in the studied alloy exists in the form of Al₃Er,only a few of Er in α-Al based solid solution .Primary Al₃Er particles formed during solidification were often found at the center of aluminum grains and acted as heterogeneous nucleus, also increased the rate of nucleation, therefore the grain are remarkably refined. Trace Er addition to high pure aluminum is able to increase the mechanical properties of high pure Al, which is caused by fine grain strengthening, substructure strengthening and precipitation strengthening. The recrystallization temperature of Er-doped aluminum increases above 50℃, which is caused by the pinning effect of highly dispersed fine Al₃Er precipitates on dislocations and sub-grain boundaries.

Key words: rare-earth element Er; mechanical properties; recrystallization; Al₃Er