Milling time effects on the hyperfine properties of FeCuB alloys

A Mössbauer study of (Fe₃₀Cu₇₀)₉₆B₄ (FeCuB) alloys, obtained previously by induction casting and subsequent ball milling up to 60 h, was conducted at room temperature (RT). ⁵⁷Fe Mössbauer spectra were fitted using three components: two magnetic hyperfine field distributions (HFD) with average B_hf1 and B_hf2 values plus a quadrupolar distribution (QSD) to account for disorders that are induced during the milling process. Thus, these components are respectively associated with a magnetically coupled α-iron phase (B_hf1 component), a Fe-rich containing phase with B_hf2 value smaller than that found for α-Fe (B_hf1 component), consequently attributed to the FeCuB alloy and, a Fe-poor phase responsible for the paramagnetic phase (QSD). The B_hf2 component shows fcc-type features, and the milling process produces an increase of the paramagnetic phase at the expense of the α-iron (bcc).