Analysis of the effect of the liquid phase separation on the formation of microstructure in the Sn-Fe and Al-Fe-Sn alloys

In the present paper, the wide miscibility gap in liquid phase in the Al-Fe-Sn system is well defined for the first time. A large miscibility gap extends from the Sn-Fe side and dramatically extends upon addition of Al. The evolution of the microstructure during solidification was investigated experimentally in the entire concentration range in binary SnFe and ternary Al-Fe-Sn systems using SEM/EDS, XRD and DTA/DSC techniques. The existence of Fe3Sn phase in the Sn-Fe system was confirmed. It was found that the FeAl2 phase in the ternary system participates in equilibrium with the liquid phase contrary to the binary Al-Fe system where it is formed in a solid state. All the binary phases do not demonstrate any essential solubility of the third component. Liquidus and solidus projections, melting diagram, isothermal section at 850 degrees C, vertical sections on isoconcentrates 10, 20 and 35 at.% Sn and a Scheil reaction scheme for the Al-Fe-Sn system covering the whole concentration range were constructed for the first time.