Effect of iron on wear behavior of as-cast and heat-treated hypereutectic Al–18Si–4Cu–0.5Mg alloy: A Taguchi approach

Abstract

This study describes the influence of Fe (wt%) on the microstructure, hardness, and wear behavior of Al–18Si–4Cu–0.5Mg– XFe ( X = Fe, at 0.4, 2.0, and 5.0 wt%) hypereutectic Al–Si alloy. The range of alloys was selected on the basis of literature study. The literature revealed that most of the studies on the effect of iron have been focused on either hypo-eutectic Al–Si alloys or lower levels of iron in the alloy. As Fe-rich intermetallic compounds are high melting point compounds, it is expected that they should improve the high temperature strength of the Al–Si alloys. The higher iron contents were specifically selected to obtain the advantage of high temperature stability leading to high wear resistance. Microstructure has been characterized using optical microscopy, scanning electron micrography, and image analysis studies. Maximum hardness of the alloy was obtained when solutionized (at 500 ℃) for 4 h followed by artificial aging (at 190 ℃) for 6 h. Heat-treated samples with only maximum hardness were further tested for wear behavior. The wear behavior of alloy in the as-cast and heat-treated conditions has been analyzed using Taguchi approach and analysis of variance analysis to find out the factors that affect wear significantly.