Structural and thermal properties of the Fe-based alloys prepared by mechanical milling

다국어 초록 (Multilingual Abstract)

Nanocrystalline FeCoNi and FeCoNiSi powdered alloys were prepared by mechanical milling process(MA). Using X-ray diffraction patterns, we experimentally proved that when MA reached a time of 50 h, it led to adecrease of the crystallite size down to 20 nm and 32 nm for FeCoNiSi and FeCoNi, respectively. However, the dislocationdensity increased, reaching the highest value for the alloy associated with silicon. Nevertheless, this high energyball-milling process is not used only for the refining of microstructure, but also to induce either a chemical reactionbetween the powdered chemical elements or a phase transformation, such as the allotropic transformation of HCP-Coto FCC-Co and the formation of highly disordered Fe-based solid solutions. Thermal stability of the milled mixtureswas investigated by DSC from 25 up to 700 oC at a heating rate of 10 oC/min. Various milled samples were first annealedat specific temperatures and then analyzed using X-ray diffraction, which demonstrated the stability of the evolvedphases during subsequent heating and the formation of some metallic oxides, such as Fe3O4, Fe2O3 and FeO, particularlyfor the elevated annealing temperatures.