Tribological Characterization of the Modified Cast Al–Si Eutectic Alloys

Abstract

The focus of this investigation is on the modification of Fe-rich intermetallics morphology and wear and friction properties of eutectic Al–Si alloys. Eutectic Al–Si specimens were fabricated by tilt casting after addition of different amounts of iron and manganese to the molten alloy. Dry sliding tribological behavior of the samples was investigated using a reciprocating wear tester at room temperature in atmospheric environment. It is found that the addition of iron up to 1.5 wt % to the alloy decreases the wear resistance of the alloy owing to the formation of brittle plate-like interme-tallic compounds of β-Al₅FeSi. As Manganese is added to the β-containing alloy up to the half of the iron content (corresponding to a Mn/Fe ratio of 0.5), the platelet phases are completely replaced by the star-like intermetallic α-Al₁₅(Fe, Mn)₃Si₂ resulting in improved wear resistance of the alloy. Introducing 0.8 wt.pct Mn to the alloy containing 1.6 wt % Fe did not convert the plate-like beta intermetallics to the modified alpha compounds completely and had no impressive impact on the wear rate of the alloy.