Effects of Sb, Sr, and Bi on the material properties of cast Al-Si-Cu alloys produced through heated mold continuous casting

Rare earth metals can create a fine eutectic Si structure in cast Al-Si_10.6-Cu_2.5 (ADC12) alloys produced through heated mold continuous casting. Fine and spherical eutectic Si phases are created in the ADC12 alloys through the addition of Sr0.04, and fine lamellar eutectic Si phases are created through Sb and Bi addition. Crystal orientation on the face perpendicular to the casting direction is formed by [110]; however, this uniform formation is collapsed in the ADC12 alloy with an increasing amount of Sr addition, such as Sr > 0.04%. The shape of the eutectic Si is statically analyzed, and the effects of the eutectic Si characteristics on the mechanical properties are examined experimentally. On the one hand, the mechanical properties of the ADC12-Sr alloy increase with increasing Sr content because of the fine eutectic Si, the randomly orientated crystal formation, and so on. On the other hand, the material ductility increases in the ADC12 alloy with increasing addition of Sb and Bi elements. A high fracture strain of approximately 14% is obtained for the ADC12-Bi1.5 alloy.