Dry sliding wear behaviour of hypoeutectic Al-Si alloys containing excess iron

The effect of Fe content on the wear behaviour and tensile properties of Al-Si alloys was studied. It is shown that as the amount of Fe in the alloy was increased to similar to 0.7 wt-% an improvement of similar to 10% was observed in the wear resistance under applied loads of 20, 30 and 40 N. Further addition of Fe up to 1.8 wt-%, however, lowered the wear resistance by about 30, 35 and 55% under applied loads of 20, 30 and 40 N respectively. This behaviour can be attributed to the formation of needle-like Al5FeSi intermetallics in the matrix. For the higher Fe contents, although the hardness of the alloy increased, the crack sensitive nature of these intermetallics also became severer. This in turn led to higher tendency of the alloy to microcracking, higher wear and lower tensile properties.