Structural and thermal study of Fe-Ni-Si-B powders prepared by mechanical alloying

Fe39Ni39Si10B12 alloys, in both a nanostructural and a disordered amorphous-like state, were produced from different precursors using the mechanical alloying technique. Products were examined as a function of the milling time as well as the precursors. Milling times up to 80h were used and the progress in the alloying effect was analysed by X-ray diffraction, scanning electron microscopy (with energy dispersive X-ray microanalysis) and differential scanning calorimetry. The results show that at least partial amorphisation takes place. The newly formed amorphous structure and the residual crystalline phases have reached equilibrium after 40h milling. The crystallisation enthalpies were evaluated and the resulting phases were identified. The products of crystallisation include fcc(Ni,Fe), Fe3B, Fe3Si, Ni31Si12 and Fe5Si3. The results suggest that the formation of the amorphous structure have been promoted by diffusion of Fe into Ni-rich lattices.