Effect of Primary Silicon Refinement on Mechanical and Wear Properties of a Hypereutectic Al-Si Alloy

This study explores the effect of primary silicon refinement of hypereutectic Al-Si alloy on the mechanical and wear properties. Refinement has been carried out by purging N2 into hypereutectic Al-Si alloy melt for different period of time. Hypereutectic Al-Si alloy with 16.2 wt.% of Si was taken for the study and purged by N2 gas for different time. Hypereutectic alloy under different conditions was characterised for various properties. X-ray diffractometer (XRD) analysis doesn’t show formation of any nitride but optical microscopy (OM) and scanning-electron microscopy (SEM) results show modified/refined morphology of silicon. Mechanical and dry sliding wear properties were evaluated at ambient temperature and results reveal improvement in these properties. Worn surfaces were also studied under SEM and 3D-profilometer for surface analysis. Results indicate that at low load/sliding velocity, wear is oxidative/mild in nature, whereas, oxidative-metallic/severe wear is observed at high load/sliding velocity.