Structural and Mössbauer studies of Fe1−xAlx alloys over the entire composition range

Metastable Fe_1?xAl_x alloys over the entire composition range have been investigated by X-ray diffraction and Mössbauer effect measurements. Alloys with x less than 0.55 are bec, whereas those with x>0.9 are fce, in between, the samples are amorphous. The Mössbauer spectra at 300 K for the bce alloys with x<0.5 consist of a broadened sextet and the spectra for the alloys with x≥0.5 are quadrupole-split doublets with a slight asymmetry. The magnetic hyperfine field at 4.2 K decreases monotonically with Al concentration from 340 kOe in pure Fe to zero at x=0.7. The isomer shift increases essentially linearly with Al concentration, and reaches a maximum at x=0.75. It is noted that at the boundary of x=0.55 separating the bce and the amorphous states, there is no discernible change in elther hyperfine field or lsomer shift.