| Abstract Scope |
Fe is readily incorporated as an impurity during primary aluminum production, and its precipitation as platelet-shaped β-Al9Fe2Si2 degrades mechanical properties. Introducing Mn as an "Fe corrector," which converts β-Al9Fe2Si2 into the less harmful α-AlMnFeSi, has been widely investigated in secondary scrap-based, high-Fe Al-Si alloys. However, in low-Fe Al-Si alloys, plate-shaped Al9Fe2Si2 was consistently observed in the eutectic region upon addition of Sr modifier, despite sufficient Mn addition, along with changes in morphology. This indicates that the Fe-neutralizing effect of Mn is also governed by other alloying elements, such as Sr. This study investigates how Mn, Fe, Sr, and cooling rate influence the formation of multiple Fe-rich intermetallic compounds through systematic microstructural observation, thermodynamic analysis, and first-principles calculations. These findings provide general guidelines for designing sustainable Al-Si casting alloys with minimally compromised properties. |