Influence of Magnetic Stirring and Eutectic Front Velocity on the Solidified Microstructure of Al-18 wt.% Si Alloy

The microstructure of hypereutectic Al-Si alloys is crucial in determining their mechanical properties and overall performance in engineering applications. This paper investigates the effect of a rotating magnetic field (RMF) and eutectic front velocity on the microstructure of hypereutectic Al-18 wt.% Si alloy. The hypereutectic samples were solidified using five different front velocities (0.02, 0.05, 0.09, 0.2, and 0.4 mm/s) with an average temperature gradient (G) of 8 K/mm in a crystallizer equipped with an RMF inductor. The samples were solidified into two sections. The first section solidified without stirring, while the second section solidified with stirring using RMF at an induction (B) of 7.2 mT. The length, angular orientation of eutectic Si lamellas, and interlamellar distances were measured in both the non-stirred and the stirred sections to evaluate the impact of RMF and front velocity on the eutectic structure. The results revealed that the application of RMF and the increase in front velocity during solidification led to the significant refinement of the eutectic structure. These findings highlight the potential of RMF and front velocity manipulation to enhance the microstructure of hypereutectic Al-Si alloys, with practical implications for the development of high-performance materials.