Formation of Fe-rich intermetallics in Al–5.0Cu–0.5 Fe alloys with different Mn additions

The formation of Fe-rich intermetallics in gravity die cast and squeeze cast Al-5.0 wt-% Cu-0.5 wt-% Fe alloys with different Mn contents was investigated. In gravity die cast alloys, the predominant Fe-rich intermetallics are AlmFe and beta-Fe with lower Mn contents, but alpha-Fe and Al-6(FeMn) are predominant when the amount of Mn increases. A lower amount of added Mn is required in the squeeze cast alloys because the applied pressure is favourable for the formation of Chinese script Fe-rich intermetallics and for preventing precipitation of the needle-like intermetallics.The formation temperature increases for alpha-Fe and AlmFe but decreases for beta-Fe with an increase in the applied pressure.