Investigation on Microstructure and Mechanical Properties of Hypereutectic Al-Si Alloy Produced by Electro-thermal Method

The hypereutectic Al-Si alloy produced by electro-thermal methods was modified with P and RE,then the microstructure and mechanical properties of alloy were analyzed.The results show that the complex modification of P and RE obviously improves the shape of Si particles,the size of primary Si particles is obviously decreased.The eutectic Si particles are changed from long pin shape into fine particles or short bar shape.The tensile strength and ductility of alloys is improved from182 MPa and 0.22% to 205 MPa and 0.26%,which are increased by 12.6% and 18.2%,respectively.But compared to hypereutectic Al-20Si alloy produced by pure aluminum,the tensile strength and ductility of alloys produced by electro-thermal methods are lower.The reason is that the content of Fe in hypereutectic Al-Si alloy produced by electro-thermal methods is higher.