An investigation of mechanically alloyed Fe–Al

An X-ray diffraction and 57 Fe Mössbauer effect spectra study of mechanically alloyed Fe 100− x Al x is presented. Alloys with 0≤ x≤60 were prepared from elemental powders in a high energy ball mill. Alloys of the composition Fe 50Al 50 were also studied in detail as a function of milling time in order to better understand the phase formation in these alloys. X-ray measurements showed all fully milled samples to be of the bcc structure. Up to x=40, Mössbauer effect spectra showed the alloys to be ferromagnetic with a decreasing mean hyperfine field as a function of x. For x>40 no magnetic splitting was observed indicating that the alloys are paramagnetic at room temperature. Hyperfine field distributions of the ferromagnetic alloys can be interpreted in terms of Fe neighbor environments as a function of Al content. As a function of milling time, the composition of the Fe 50Al 50 alloy may be described in terms of changing proportions of three different phases; a ferromagnetic bcc phase (FeAl y), a paramagnetic fcc phase (AlFe y) and a paramagnetic bcc phase (FeAl). The relative proportions, compositions and microstructures of these phases may be understood from the combined X-ray diffraction and Mössbauer effect measurements.