Formation kinetics of nanocrystalline Fe-4wt.%Al solid solution during ball milling

Formation of nanocrystalline Fe-4 wt. % Al solid solution has been achieved through SPEX ball milling of blended elemental Fe and Al powders. Differential scanning calorimetry (DSC) and x-ray diffraction (XRD) have been employed to follow the structural evolution during the ball-milling process. Exothermic peaks exhibited in DSC diagrams of the powders milled for 10 to 60 min yielded thermal enthalpies corresponding to the formation of Fe-4 wt. % Al solid solution, from which the kinetics of formation were found to follow the Johnson-MeN-Avrami equation. Assessment of the kinetic parameter n reveals a diffusion controlled mechanism, in which grain and interphase boundaries may play a crucial role, during the solid solution formation of Fe-4 wt, % Al.