Mössbauer characterization of an amorphous steel with optimal Mo content

Abstract Three amorphous steel alloys, Fe71.2−xC7.0Si3.3B5.5P8.7Cr2.3Al2.0Mox (x = 0, 4.5 and 6.5 at.%), have been produced by the melt-spinning technique and characterized by X-ray diffraction and transmission Mossbauer spectrometry (TMS). TMS allows us to study the local environments of the Fe atoms in the glassy state, showing the changes in the amorphous structure due to the addition of Mo. A reduction of the mean hyperfine field is observed as the amount of Mo increases. With intermediate Mo content, this reduction is associated to the substitution of Fe by Mo in a disordered magnetic Fe-rich structure, whereas for high Mo content, this structure is destroyed leading to an increase of paramagnetic environments. Finally, the relationship between the glass forming ability (GFA) of these alloys and their local structure determined by TMS will be discussed.