Initial stage of mechanical alloying in the Fe–C system

Abstract

Mössbauer spectroscopy (MS), X-ray diffraction, transmission electron microscopy (TEM), Auger spectroscopy, magnetic measurements and differential thermal analysis (DTA) were used to study the initial stages of mechanical alloying in the Fe–C system. The mechanical alloying of Fe and C powder mixtures with the atomic ratio 85:15 in a planetary ball mill was taken as an example. It has been shown that the initial stage involves the formation of nanostructure in the α-Fe particles, penetration and segregation of carbon along the α-Fe grain boundaries, formation of the amorphous Fe–C phase in the interface regions consisting of the boundary and close-to-boundary distorted zone. The carbon concentration in the amorphous Fe–C phase is estimated at 25 at.%. The amount of the amorphous phase reaches 67 at.% (67% of all the Fe and C atoms are in this phase).