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The influences of P and rare earth (RE) complex modifier on the microstructure and mechanical properties of hypereutectic Al-21%Si alloy were studied. The ingots were made by metal mold casting and the proportion of Ce+P ingredient was different. The result showed that the size of grains could be refined obviously by the Ce+P modifier and the effect of phosphorus was more intensive. The primary silicon crystal was refined, while the needle-like eutectic silicon was turned fibrous or short. The alloy mechanical properties had the best performance when 0.08%P and 0.6%Ce were added. The modification of primary silicon grains mainly depended on the heterogeneous nucleation mechanism, and the metamorphic mechanism of eutectic silicon was explained by adsorbing-twinning theory. The strengthening mechanism of experimental alloy was also discussed. The σb, 20 ℃ increases from 236.2 to 287.6 MPa and σb , 300 ℃ increases from 142.5 to 210 MPa.
The influences of P and rare earth (RE) complex modifier on the microstructure and mechanical properties of hypereutectic Al-21% Si alloy were studied. The ingots were made by metal mold casting and the proportion of Ce + P ingredient was different. The result showed that the size of grains could be refined obviously by the Ce + P modifier and the effect of phosphorus was more intensive. The primary silicon crystal was refined, while the needle-like eutectic silicon was turned fibrous or short. The alloy mechanical properties had The modification of primary silicon grains mainly depended on the heterogeneous nucleation mechanism, and the metamorphic mechanism of eutectic silicon was explained by adsorbing-twinning theory. The strengthening mechanism of experimental alloy was The σb, 20 ℃ increases from 236.2 to 287.6 MPa and σb, 300 ℃ increases from 142.5 to 210 MPa.