Phase transformations during mechanical alloying of Fe-30% Al-20% Cu

Nanostructured disordered iron-aluminium-copper alloy of Fe-30% Al-20% Cu composition was prepared by mechanical alloying of the elemental powders in a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. The transformation of the phase depends upon the milling time. With the increase of milling time all Al and Cu atoms became dissolved in the bcc Fe and the final product of the MA process was the nanocrystalline Fe(AI,Cu) solid solution with a mean crystallite size of about 9 nm. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Magnetic properties were also investigated and were related to the microstructural changes. The unprocessed sample showed a soft ferromagnetic behavior (Hc approximate to 173 A/m) whereas alloyed samples at the early stages of processing reached a hardening ferromagnetic behavior (Hc approximate to 15277 A/m). For longer milling time the magnetic behavior slightly softened becoming a semihard ferromagnetic (Hc approximate to 5500 A/m). (C) 2013 Elsevier B.V. All rights reserved.