Multicomponent mechanical alloying of Fe-Cu-Nb-Si-B

The mechanical alloying (MA) process of an elemental powder mixture of Fe73.5CuNb3Si13.5B9 was investigated in this paper. X-ray and electron diffraction results showed the MA product was an ct solid solution with BCC structure. Transmission electron microscopy (TEM) dark field image revealed this cu solid solution had a nanocrystalline structure and the grain size was about 10 nm. The results of Mossbauer analysis indicated that a part of the powders was superparamagnetic owing to the extremely fine size obtained by ball milling. The Fe atoms occupy four kinds of ferromagnetic local environments. The values of the hyperfine fields of three of the corresponding subspectra decreased with milling time because of the increasing alloying level. The fourth subspectrum could be attributed to the contribution of iron atoms in nanograin boundaries. (C) 1998 Elsevier Science S.A.