Influence of Bi and Sb Contents on Eutectic Growth of Al-Si Alloy: An Experimental Study

Herein,we addressed the modification of Al-Si alloy with Bi and Sb modifiers.The influence of the mass fraction of Bi and Sb dopants on the eutectic growth characteristics,including the condensation curve,eutectic growth temperature(T_EG) and extent of undercooling(ΔT_EG),was experimentally investigated with the lab-built and computer controlled test platform for optimization of the modifier contents.The results show that the mass fractions of Bi and Sb all had a major impact.For example,as the Bi-content increased from 0 to 1.0%(wt),T_EG decreased from 572.5℃ to a constant of 569.2℃,with ΔT_EG being in 0℃~3.8℃ range;addition of Sb had a similar effect.We suggest that when it comes to refining eutectic Si-phase,the optimized mass fractions may be 1.0% Bi and 0.55% Sb.