A study of the solid state 'amorphization' reaction in Fe58Ta42 by diffraction and Mossbauer spectrometry

The solid state 'amorphization' reaction produced by the mechanical alloying (MA) of samples of the eutectic alloy Fe58Ta42 has been studied using x-ray and neutron diffraction and Fe-57 Mossbauer spectrometry. The consumption of the parent elements as a function of time of MA treatment has been derived from the reduction in intensity of their Bragg peaks in the diffraction patterns. The change of volume fraction of the parent ct-iron phase with increasing time of MA treatment has been determined from the reduction in intensity of the sextet in the Mossbauer spectra. The diffraction data and spectrometry data are in good overall agreement and both show that the reaction is very rapid in this eutectic alloy and that the parent iron and tantalum powders are transformed into an amorphous phase after only 6 h MA treatment in a conventional Spex 8000 high-energy ball mill. In detail, the consumptions of the parent elements derived from the two kinds of measurement are slightly different. This is possibly because the diffraction data represent an average over the whole sample while the Mossbauer spectrometry data are site specific.