Moessbauer spectroscopy of amorphous Fe-B alloys

Binary Fe-B amorphous alloys containing 12 - 25 at % B were studied by 57Fe Moessbauer spectroscopy. The spectra were examined by Fourier analysis and near-neighbor configuration analysis. The characteristic concentration dependence of the internal field distribution was explained by the interactions between iron and boron atoms in different ways depending on the boron content and the microstructure of the amorphous matrix. Alloys with boron content below 20 at % exhibited well-developed short range order with the bcc-like near-neighbor configuration, while Fe-25 at % B and slowly-quenched Fe-12 and 13 at % B alloys showed a considerable fraction of chemical order of the Fe3B type. The existence of chemical clusters in Fe-25 at % B suppressed the nucleation of Fe2B precipitates, and this alloy was therefore the most thermally-stable. (author)