Effect of Zn Addition on the Structural, Mechanical and Tribological Properties of Al12Si (EN AC 44100) Alloy

In this study, the effects of 10 wt% Zn addition on the microstructure and properties of Al12Si EN AC 44100 alloy were investigated. For this purpose, EN AC 44100 and EN AC 44100 + 10 wt%Zn alloys were fabricated by permanent mold casting. The microstructural examinations were performed using standard metallographic techniques. The phases in microstructures were identified by energy dispersive spectroscopy and X-ray diffraction analyses. The yield strength, ultimate tensile strength, and elongation to fracture of the alloys were determined by tensile testing after measuring their Brinell hardness. The tribological properties of the alloys were examined using a ball-on-disk type wear test apparatus. It was observed that the microstructure of the EN AC 44100 alloy consists of aluminum-rich α, primary silicon and β (Al–Fe–Si) phases together with the eutectic Si particles. The addition of zinc resulted in a significant increase in the hardness and the strength of EN AC 44100 alloy but a considerable decrease in its friction coefficient and wear volume by modifying the microstructure of it. The modification caused a reduction in the size of α grains and eutectic silicon particles. Effects of zinc addition on the mechanical and wear properties of the EN AC 44100 alloy were discussed in terms of the observed microstructural changes.