Study of the Microstructural, Thermal, and Magnetic Properties of High-Energy Ball-Milled Nanocrystalline Fe(Al)

Abstract

In this work, structural, microstructural, thermal, and magnetic properties of a Fe-25at%Al alloy produced by high-energy mechanical milling were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM) techniques. At the early stage of the milling process, three phases, namely, Fe, Al, and Fe(Al), coexist in the milled powder. After 20 h of milling, the results of the refinement of the XRD pattern reveal the formation of the supersaturated bcc-Fe(Al) solid solution with a crystallite size of 10 nm. The DSC curves show several overlapped exothermic peaks associated with the relaxation of the deformed structure and various phase transitions, such as the formation of Al13Fe4 and Fe3Al intermetallic. During milling times, the alloyed samples have a hard-ferromagnetic behavior, where Hc varies from 628 Oe to 746 Oe when the milling time increases from 4 to 40 h. The magnetic properties were related to the microstructural changes.