Microstructural analysis of interfacial reaction between molten aluminium and solid iron

The microstructure of solid iron and molten aluminium couple was examined at the interface. The phases were identified as Fe2Al5 and FeAl3. The former grows faster and is the major phase while the latter is easily detectable at the later stages of reaction and dissolves partially within molten aluminium. The kinetics of reaction at the interface may result in the formation of Fe2Al5 as the major constituent instead of FeAl3 in contradiction with thermodynamic principles. It was further shown that it is possible to miss FeAl3 detection due to small quantity of FeAl3, similarity of XRD spectra of both phases and spalling, remelting and dissolution of FeAl3 into molten aluminium with time.