The effects of La and Er on the microstructure and mechanical properties of cast Al-13Si-5Cu-2Ni-1Mg alloy were investigated by OM

SEM

EOS and tensile testing.The results reveal that La has a stronger modification effect on eutectic silicon

forming bulk and long needle-like La-rich phases in the alloy

and Er can reduce significantly the secondary dendrite spacing

and massive

short rod-like Er-rich phases can be generated in the alloy.With 0.2% La and 0.2% Er compound addition

the secondary dendrite spacing

primary silicon

eutectic silicon and intermetallic compound can be refined at the same time.The interaction of La and Er can inhibit the growth of RE-rich phase

and the RE-rich phase with a small size and a dispersed distribution can be introduced into the alloy

so the tensile performance presents desirable

where the tensile strength of the alloy can reach 274 MPa and 91 MPa at 25℃ and 350℃

respectively.