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 electro n diffraction results showed the MA product was an ct solid solution w ith BCC structure. Transmission electron microscopy (TEM) dark field i mage revealed this cu solid solution had a nanocrystalline structure a nd the grain size was about 10 nm. The results of Mossbauer analysis i ndicated that a part of the powders was superparamagnetic owing to the extremely fine size obtained by ball milling. The Fe atoms occupy fou r kinds of ferromagnetic local environments. The values of the hyperfi ne fields of three of the corresponding subspectra decreased with mill ing time because of the increasing alloying level. The fourth subspect rum could be attributed to the contribution of iron atoms in nanograin boundaries. (C) 1998 Elsevier Science S.A.