Mechanical properties, tribology and electrochemical studies of Al/Fly ash/eggshell aluminium matrix composite

This work was carried out to investigate the effect of carbonized eggshells (CES) and fly ash on the microstructure, mechanical properties, wear, and corrosion characteristics of Al-Si12. The weight fraction (wt.%) of the CES particles was kept constant at 2.5 wt.%, while that of fly ash was varied at 2.5 wt.%, 5.0 wt.%, 7.5 wt.%, and 10.0 wt.%. The selected fabrication route was stir casting. The x-ray diffraction (XRD) analysis of the cast aluminum matrix composites (AMCs) revealed the presence of phases including α-aluminum, SiO₂, and Si with the formation of the intermetallic CuAl₂ phase. The microhardness of the cast samples increased with increasing weight fraction of the reinforcements up to the 7.5 wt.% fly ash sample. The tensile strength and compressive strength were highest for the 2.5 wt.%/CES 2.5 wt.%. Tribology studies showed that the lowest wear rate of 4.91 × 10^-5 mm³/Nmm was obtained for the 2.5 wt.% fly ash sample, while the corrosion studies showed that the corrosion rate of 2.70 × 10^-5 g/hr was lowest for the 2.5 wt.% fly ash as well.