Kinetics and phase transformation evaluation of Fe-Zn-Al mechanically alloyed phases

Fixed composition ratios of Fe and Zn corresponding to γ-(Fe3Zn110), Γ1-(Fe5Zn21), δ-(FeZn7), and ζ-(FeZn13) with the addition of 5 pct Al (wt) were ball milled in an argon gas atmosphere to form homogenous alloys. Nonisothermal kinetic analyses of the mechanically alloyed materials, based on differential scanning calorimetry (DSC) measurements, revealed two diffusion-controlled processes during the evolution of the δ+5 pct Al and ζ+5 pct Al compositions with activation energies of 227±2 and 159±1 kJ/mole, respectively. Other endothermic and exothermic reactions detected for these compositions are consistent with the Fe-Zn-Al equilibrium phase systems with respect to the formation of the Fe3Al, Fe2Al5, and δ-FeZn7 phases Based on the evidence of FeAl2 formation at 440 °C for the ζ+5 pct Al composition from X-ray diffraction (XRD) and DSC measurements, the revision/re-evaluation of the Fe-Zn-Al equilibrium phase diagrams is proposed. The Γ+5 pct Al and Γ1+5 pct Al compositions evolved similarly through the same fields, except at 400 °C, where the former consisted of α-Fe + Γ + δ, while the later was without the Γ phase.