Effect of Ce on morphology of α(Al)–Al2Cu eutectic in Al–Si–Cu alloy

The effect of Ce addition on the morphology of the α(Al)–Al2Cu eutectic in Al–Si–Cu alloy was investigated using thermal analysis, light microscopy, scanning electron microscopy, focused ion beam and energy dispersive analysis. The results show that the eutectic α(Al)–Al2Cu forms within small space between dendrites, silicon and AlSiFeMn plates. Eutectic Al2Cu is not lamellar but degenerated. However, Al2Cu in Ce-modified alloys is more compact. Ce partially dissolves in Al2Cu, which is a viable reason for the formation of coarser Al2Cu. The addition of Ce also increases the microhardness of the α(Al)–Al2Cu eutectic by almost 10% compared with the basic Al–Si–Cu alloy.