Effects of Cu content on microstructure and mechanical properties of Al-14.5Si-0.5Mg alloy

► Variable Copper content can change morphology of the Iron-rich phase in Al-14.5Si-0.5Mg alloy. ► The acicular β-Al5FeSi was found only in the high-Cu alloy. ► In the low-Cu alloy, Al8Mg3FeSi6 was the Fe-bearing phase. ► Tensile testing indicated that the low-Cu alloy containing Al8Mg3FeSi6 had higher UTS and elongation than the high-Cu alloy containing the acicular β-Al5FeSi.