Characteristics Improvement by Inclusion of Phosphorous in AL-20SI

Abstract

This study study focused on enhancing the mechanical properties of hypereutectic Al-Si alloys through the addition of phosphorus (P). The research investigated how different levels of phosphorus affected the alloy's microstructure and mechanical characteristics. Results showed that phosphorus effectively refined the coarse primary silicon crystals and modified large needle-like eutectic silicon into finer fibrous or lamellar structures. However, excessive phosphorus had adverse effects on primary silicon refinement. Alloys with 0.02% to 0.03% phosphorus demonstrated optimal grain size and improved mechanical properties compared to unmodified alloys. Specifically, the Vickers hardness decreased from 81 to 57, indicating increased plasticity, strength, and wear resistance.