A MICROSTRUCTURAL STUDY OF MECHANICAL ALLOYING OF FE AND SN POWDERS

Elemental Fe and Sn powders in the ratio of 1 : 2 were ball-milled for various times at room temperature, and phase transformations in the powders were studied by Fe-57 and Sn-119 Mossbauer spectrometries, transmission electron microscopy, and x-ray diffractometry. Although Fe-Sn alloys are not obvious candidates for solid-state amorphization reactions, an amorphous phase formed after only a few hours of ball milling. Nanocrystalline intermetallic FeSn2 particles nucleated and grew within the amorphous phase, and FeSn2 became the major phase after 10-20 h of ball milling. These small particles were superparamagnetic, and were above the blocking temperature at room temperature.