Preparation and Characterization of Fe_(36)Co_(36)B_(20)Si_4Nb_4 Nanocrystalline / Amorphous Matrix Composite

摘要

In this paper, we report a Fe-based nanocrystalline-amorphous matrix composite synthesised via partially crystallising an amorphous alloy. The microstructure of the composite was characterize. An amorphous rod of 2mm in diameter was initially prepared via injecting the melted Fe_(36)Co_(36)B_(20)Si_4Nb_4 alloy into a copper mould in vacuum, which was confirmed to be completely amorphous by X-ray difraction(XRD). Differential scanning calorimeteric (DSC) curve shown that the span △Tx of the supercooled liquid region and the reduced glass transition temperature (Tg/Tm)for the amorphous alloy are 40 K and 0.615, respectively. The composite composed of nanocrystalline particles homogeneously dispersed in an amorphous matrix was prepared by isothermal annealing. In this course, the amorphous Fe-based sample was held for different time at different temperature. The types of the nanocrystalline phases obtained in different annealing conditions were characterised by XRD and selected-area diffraction pattern (SAED). The crystallization behavior of the amorphous Fe-based alloy was discussed.