Modification and Refinement of Al-23Si Alloy Processed by Addition of Nano-Metal-Phosphate

Abstract

This research investigates the effect of Nano-Metal-Phosphate on Si particles through solidification in hypereutectic Al-Si alloys. Which means the merge of modification and refinement with the addition (0.01-0.03) % of Nano-Metal-Phosphate produced by a stir casting. The process synchronizing effects of Nano-Metal-Phosphate that relates to the AlP and Al2O3 formation. These include the following, the effect of Al2O3 at the interfaced between the Al phase and Si particles for obstacle the growth and enhance the refinement of the primary Si and the impact of AlP act as sites of heterogeneous nucleation for eutectic Si. Microstructures analysis revealed that both the fundamental and eutectic Si particles were significantly modified and refined. The primary Si grains were refined from star frames to polygon forms, and their edges were more regular. The platelet eutectic Si grains were also modified into the delicate fibrous forms. Resulting in significant ductility enhancement that could have great potential for numerous applications. Besides, studies microstructure and corrosion behaviour by optical and scanning electron microscopy, XRD and electrochemical cyclic polarization.