Effect of Elements Cerium and Lanthanum on Eutectic Solidification of Al-Si-Cu Near Eutectic Cast Alloy

摘要

The properties of Al-Si-Cu cast alloys are strongly affected by eutectic Al-Si and Al-Cu phases. The characteristic parameters of these two phases with additions cerium 1wt % (Ce) and lanthanum 1 wt % (La) were investigated in Al-11Si-2Cu near eutectic alloy using computer-aided cooling curve thermal analysis. As a result, the La additive showed the highest (T_n~(Al-Si)) while the Ce additive showed very little effect. In addition, the growth temperature (T_G~(Al-Si)) is decreased by adding Ce compared to the base alloy and La addition. Additives showed an increase of recalescence magnitude(ΔT_R~(Al-Si)). Addition La and Ce increased the nucleation and growth temperature of Al-Cu phase. The microstructure analysis on the silicon morphology showed that 1 wt % La and 1 wt % Ce additions play refiner role in Al-Si-Cu near eutectic alloys. Findings are also confirmed by aspect ratio of eutectic silicon phase.