<p>Secondary aluminum alloys offer substantial reductions in energy consumption and carbon emissions, but elevated iron impurities in recycled feedstocks promote the formation of Fe-bearing intermetallics that degrade mechanical performance. This article demonstrates how different concentrations of Y alloys (0, 0.15, 0.3 and 0.6 wt.%) can be utilized to optimize the Fe-bearing phase and improve the mechanical characteristics of secondary as-cast 6061 aluminum alloys. The results indicate that α-Al dendrites and α-Al₁₅(Fe,Mn)₃Si₂ phases are easily refined with introduction of Y element, among which the 0.3Y alloy consists of the finest dendritic structure and α-Fe phases. Y alloying also induces the formation of an Al₂Si₂Y ternary intermetallic, as supported by microstructural characterization and thermodynamic analysis based on formation enthalpy and phase-diagram considerations. The Al₂Si₂Y particles preferentially decorate and adhere to α-Fe surfaces, thereby constraining the independent growth of α-Fe. Additionally, the UTS and EL of the 0.3Y alloy are separately 199.2&#xa0;MPa and 9.9%, which increase by 19.6 and 6.6% compared to the 0Y alloy. Simultaneously, the 0.6Y alloy possesses the optimum elongation corresponding to 14.5%. The considerable increase in mechanical characteristics is primarily ascribed to the refinement of α-Al dendrites and α-Fe phases.</p>