Mechanical alloying studies in the Gamma (Fe sub 3 Zn sub 10 ) and Gamma sub 1 (Fe sub 5 Zn sub 21 ) single and mixed phase compositions

Homogeneous or uniform crystalline materials are obtained following the ball milling of pure elemental powders of Fe and Zn in proportions to yield single phases Gamma (Fe sub 3 Zn sub 10 ), Gamma sub 1 (Fe sub 5 Zn sub 21 ), and Gamma + Gamma sub 1 mixed phase (Fe sub 25 Zn sub 75 ). Differential scanning calorimetry (DSC) measurements of the as-milled materials show characteristic stages in the temperature range of 50-600 deg C prior to establishing stable equilibrium. The activation energies determined from kinetic analyses range from 49-189 kJ/mole in this materials. A characteristic stage at 130 deg C marking the distinct evolution of the Gamma and Gamma sub 1 phases from the intermediate or mixed phase composition is identified from XRD measurements. The identification of a unique Fe site with a quadrupole splitting (QS) of 1.5 mm/s in corroboration with x-ray diffraction (XRD) shows that this stage marks the onset of an in situ transformation prior to the distinct evolution of the homogeneous phases. The Mossbauer effect measurement of the as-milled materials are resolved in terms of four unique Fe sites with QS of 1.1, 0.241, 0.073, and 0.0772 mm/s.