The present work describes the development and characterization of mechanical properties of an Al-Mg based die-cast alloy (ALDC6-10Si) for spider arm components in washers. The effect of the addition of silicon (10 wt.%) and magnesium (2.7 wt.%) on the microstructure and mechanical properties of the developed ALDC6-10Si alloy was evaluated. The optical microscopy images and energy dispersive x-ray spectroscopy profiles reveal that the presence of Mg2Si in the ALDC6-10Si alloy is higher than that of commercial ALDC3 alloy. The hardness and tensile strength of the ALDC6-Si10 alloy were found to be improved due to the presence of intermetallic phases such as Mg2Si and π-Al8Si6Mg3Fe. Moreover, the formation of spheroidal primary α-Al and the refinement of the fine eutectic Si structure also enhanced the mechanical properties. In addition, a spider arm component was fabricated using the developed ALDC6-Si10 alloy and evaluated its microstructure and mechanical properties. The results indicated that ALDC6-Si10 alloy can be a better alternative for fabricating the spider arm component in washers.