Fe-VC-[Fe.sub.3]C nanocomposites produced by mechanical synthesis from various starting components

Methods of X-ray diffraction, Mossbauer spectroscopy, and electron and atomic force microscopy have been used to study the sequence of structural and phase transformations upon mechanical alloying, annealing, and compacting of iron-vanadium-carbon alloys produced from mixtures of various compositions, such as powders of Fe (70 at %) and VC (30 at %); powders of pure elements of Fe (70 at %), V (15 at %), and graphite (15 at %); powders of Fe (70 at %) and V (15 at %) and toluene. It has been shown that in all cases the mechanical alloying results in the formation of nanocomposite powders with a complex phase composition representing a mixture of an [alpha]-Fe-based solid solution, carbide-based X-ray amorphous phase, and vanadium carbide VC. The annealing and compacting lead to the formation of an Fe-VC-[Fe.sub.3]C nanocomposite. The use of liquid organic media as the source of carbon makes it possible to obtain materials with a narrow grain-size distribution and a uniform spatial distribution of carbide phases, which results in high values of microhardness, to 12 GPa. Keywords: mechanical alloying, iron, vanadium, cementite, vanadium carbide, liquid organic medium, nanocomposites, microhardness DOI: 10.1134/S0031918X12030088