Nanostructured Fe75Si10B10Nb5 powders were prepared by mechanical alloying of Fe, Si, B and Nb elements in a high-energy planetary ball mill. The structural properties and morphology changes were investigated as a function of milling time (in the 0-100 h range) by means of X-ray diffraction and scanning electron microscopy. At early stage, the dissolution of B and Si atoms into the Fe lattice leads to the formation of bcc Fe(Si,B) solid solution. After milling until 100 h, a mixture of Fe(Si,B) (similar to 20 nm) and Nb(B) (similar to 10 nm) is obtained. On the other hand, an interesting phenomenon called mechanical recrystallization, related to the formation of a crystalline phase of a partial amorphous powder (obtained at similar to 56 h), was investigated. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.