Intermetallic compound formation in Fe–Al–Si ternary system: Part II

Abstract

The phase equilibria in the Fe–Al–Si ternary system have been studied in the temperature range 600–900 °C using ternary diffusion couple experiments with pure Fe and high purity Al–Si eutectic alloy. A number of binary and ternary intermetallic compounds have been observed. Except for the FeAl 3 binary phase, the remaining intermetallics of the system, namely, Fe 2Al 5, FeAl and Fe 3Al, are observed to form as solid layers next to pure iron. The FeAl 3 phase was observed in association with the liquid which solidified into secondary and tertiary crystallization products. A number of ternary phases, namely, τ 1, τ 2, τ 4, τ 5 and τ 6 have been observed. These phases have crystallized either directly from the liquid or through the invariant or monovariant reactions. The composition of the phases and associated microstructure of each phase has been presented.