Fe–Al phase formation around SHS reactions under isothermal conditions

This study investigates the phenomena preceding and accompanying the SHS reaction between Fe and Al elemental powders during sintering. SEM and XRD analysis were used to observe the mechanisms of formation of Fe–Al intermetallic phases. The analysis of sintered material just before the SHS reaction demonstrates that in addition to the well-known Fe2Al5 phase and the low-aluminum solid solution of iron, the high-aluminum phases FeAl2 and FeAl3 are formed. The kinetics of phase transformations under isothermal conditions were investigated by DSC using the JMA (Johnson–Mehl–Avrami) model. This approach allowed us to calculate Avrami coefficients, which characterize the speed and the manner of particular phase transformations.

Research highlights▶ The processing temperature is an important parameter for isothermal sintering. ▶ There are two mechanisms of formation of Fe–Al phases. ▶ The measurements confirmed the presence of the entire spectrum of Fe–Al phases in tested sinters.