Effect of iron-rich intermetallics on the sliding wear behavior of Al-Si alloys

This study was undertaken to investigate the effect of Fe-rich intermetallics on the wear behavior of SAE F332 piston alloy. The wear behavior of Al-Si alloys was influenced by the presence of hard and brittle β-Al5FeSi intermetallics. It was shown that an increase of iron from 0.15 wt% in the base alloy to about 0.7 wt% increased the hardness and improved the wear resistance by about 10% under applied loads of 20 and 40 N. Addition of iron up to 2.5 wt% further increased the hardness, however, it decreased the wear resistance by over 70% under the same applied loads. The negative effect of intermetallics was controlled via combined effects of high cooling rate solidification and strontium modification. The wear resistance of the controlled 1.2 wt% Fe alloy was improved by about 50% compared to the unrefined alloy with the same amount of iron under applied loads of 20 and 40 N.