In this study, the microstructural evolution and amorphous phase formation of Fe42Ni28Zr8Ta2B10C10 alloy produced by mechanical alloying (MA) were investigated. This alloy is a soft magnetic material with better magnetic properties in its amorphous condition. Effects of milling time on the phase transformation, microstructure, morphological evolution and thermal behavior were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Results showed that at the early stage of milling, the powder contained a nanocrystalline alpha-Fe solid solution. Further milling decreased the crystallite size of this phase and finally the amorphous phase was produced. The amount of the amorphous phase was calculated using Rietveld methods and W powder as the internal standard and the results showed that the quantity of this phase reached about 95% after 154 h of milling (C) 2012 Elsevier B.V. All rights reserved.