Structure and magnetic properties of powders prepared by mechanically alloying 50Fe+25Al+25Si mixtures

A 50Fe + 25Al + 25Si powder mixture was mechanically alloyed in a high-ener gy ball mill, and the products of the solid-state reactions were characteri zed by x-ray diffraction and magnetic measurements. The results show that t he process involves the formation of a metastable bcc Fe < Al,Si > solid so lution, which decomposes into the ordered phases FeAl1-xSix (B2 structure) and FeSi (B20) upon heating to 700 degreesC or long-term milling. The obser ved effect of milling on the magnetic properties of the powders indicates t hat the proportion of the ferromagnetic component in the alloy decreases wi th increasing milling time as a result of the ordering of the solid solutio n and the formation of the B2 and B20 paramagnetic phases.