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

Abstract

ABSTRACT

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 Al_mFe and β-Fe with lower Mn contents, but α-Fe and Al₆(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 α-Fe and Al_mFe but decreases for β-Fe with an increase in the applied pressure.