Abstract: Effect of annealing process on microstructure and properties of the Al-Zr-Er alloy prepared by water-cooled copper mold was studied by means of hardness tester, electrical conductivity gauge and scanning electron microscope. The results show that when the addition amount of Er increases from 0 to 0.30wt%, the primary Al (Fe,Er) phase in the Al-Zr-Er alloy increases gradually, and a large number of nano-sized Al₃ (Zr,Er) particles are precipitated during annealing. During the isochronous annealing process of Al-Zr-Er alloy, hardness and electrical conductivity exist two peak positions. The first peak is at 300-400 ℃ which represents the precipitation process of Al₃Er and the second peak is Al₃(Zr, Er) at 500-550 ℃ .In the annealing process, multi-stage annealing can more fully form Al₃ (Zr, Er) particles of core-shell structure, and the hardness is improved significantly. During the three-stage annealing process, Zr and Er elements in the matrix are more fully precipitated, and the conductivity is the highest. In terms of composition, the addition of 0.15wt%Er in the Al-0.10Zr-xEr alloy shows better comprehensive properties. Although adding Zr element to Al-yZr-0.15Er alloy will increase the hardness of the alloy, the insufficient precipitation of Zr element will lead to the loss of electrical conductivity.

Key words: Al-Zr-Er alloy, conductor material, annealing process, microstructure, properties