Moessbauer studies of the mechanically alloyed Cu-30 at.% Fe

We report Moessbauer and structural studies of the mechanically alloyed Cu-30 at% Fe for milling times between 0 and 18 hours. Samples are prepared by mechanical alloying of Fe and Cu powders. X-ray diffraction and Moessbauer spectroscopy are used to study the magnetic and structural properties of the alloyed samples as a function of milling time. The results of X-ray diffraction patterns show the coexistence of bcc α-Fe and fcc Cu phases. After extended milling times, X-ray diffraction show an increase in the peaks' width, line broadening, indicating a reduction in the particles size. The position of the diffraction peaks as a function of milling time suggest the appearance of new phases. Moessbauer spectroscopy is used to monitor the phase transformation as a function of milling time. It is found that for small milling times, less than 3 hours, the spectrum is consist of six absorption lines corresponding to α-Fe. For milling times higher than 3 hours, new absorption lines start to appear which identified as γ-Fe phase and fcc Fe/Cu solid solution phase. The percentage of each of the three phases is calculated from the intensity of each subspectra after the fitting. α-Fe phase is found to decrease from 100% at milling times of 3 hours or less to 0% at milling time of 18 hours, while γ-Fe phase and fcc Fe/Cu solid solution phase are found to increase from 0% to 34%, for γ-Fe, and from 0% to 66% for Fe/Cu solid solution, for milling times of 3 hours to 18 hours. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)