An investigation of mechanically alloyed Fe-Al

An X-ray diffraction and Fe-57 Mossbauer effect spectra study of mechanically alloyed Fe100-xAlx is presented. Alloys with 0 less than or equal to x less than or equal to 60 were prepared from elemental powders in a high energy ball mill. Alloys of the composition Fe50Al50 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, Mossbauer 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 Fe50Al50 alloy may be described in terms of changing proportions of three different phases; a ferromagnetic bcc phase (FeAly), a paramagnetic fee phase (AlFey) 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 Mossbauer effect measurements. (C) 1998 Elsevier Science S.A.