Modification Effect of Mixed Rare Earths on Al-28wt%Si Alloy

The influences of RE on the microstructure and mechanical properties of hypereutectic Al-28wt%Si alloy were investigated.The results show that the addition of RE has strong modification effect on the microstructure of hypereutectic Al-28wt%Si alloy;the average grain size of primary Si phase reduces from over 200 μm to about 100 μm,meanwhile,its modification effect on the eutectic silicon is more obvious,and the eutectic silicon transforms from the tabular into the small rod-shaped;the mechanical properties improves too.