Features of nanostructural states of mechano-synthesized powder steels alloyed by Cr and Si

The paper studies the influence of alloying elements of substitution (Cr, Si) on the formation of nanostructures in powder nanocrystalline steels based on Fe-1mas. of % C obtained by means of mechano-alloyage of the initial powders of iron and graphite. The study was carried out by X-ray diffraction and magnetic structuroscopy. Carbon is distributed between the volumes of ferrite nanograin and grain boundary segregations in the nanostructure of steels. The carbon concentration in the ferrite varies between $0.2$ and $0.37$ at. % depending on the alloyage. Cr and Si increase the concentration of carbon in the ferrite as compared to non-alloy steel. The carbon concentration in grain boundary segregations varies within the range $(1.1-1.7)\cdot 10^{-5}$ mol/m$^2$. Cr lowers the concentration of carbon in segregations, while Si causes little change. The concentration of carbon in segregations is determined mainly by the grain size and the associated extent of the boundaries obtained by mechano-alloyage.