<p>This study provides mechanistic insights into the microstructural evolution and property enhancement of secondary Al-Si-Zn-Fe-Cu alloys through the addition of Ni. A systematic investigation was conducted to evaluate the effects of varying Ni concentrations on the alloys' microstructure, mechanical performance, and electrical conductivity. It was found that the microalloying effect of Ni promotes the formation of eutectic silicon and homogenizes the constituent phases. The results demonstrate that the addition of Ni up to 0.3 wt.% leads to a more uniform component distribution and refined grain structure. This promotes a significant reduction in the size and number of coarse primary silicon particles and enhances the uniformity of silicon distribution. At the optimal Ni content, the alloy exhibits substantial improvements in hardness, tensile strength, and electrical conductivity, reaching 84.5 HV, 126.16&#xa0;MPa, and 26.4% IACS (International Annealed Copper Standard), respectively. Moreover, Ni additions up to 0.3 wt.% elevate the initial melting temperature, peak melting temperature, and final melting point, while broadening the solidification range. However, when the Ni content exceeds 0.3 wt.%, it leads to the formation of primary silicon, coarsening of the Al-Ni–Fe phase, deterioration of the alloy's mechanical properties, and a reduction in electrical conductivity. These findings highlight the critical role of Ni in tailoring the morphology and distribution of silicon phases, offering valuable guidance for the design and optimization of high-performance secondary Al-Si-based materials with improved mechanical and physical properties.</p>