Crystallographic Features of Nanosized Titanium Carbide Produced from Titanium and Carbon in a Planetary-Ball Mill

Abstract

Structural changes that occur in titanium during grinding of a powder mixture of titanium and carbon in an AIR-015M planetary-ball mill are studied. Grinding of the powder mixture results in the formation of titanium carbide single crystals with particles 7–50 nm in size over the entire reaction zone. At the initial stage of grinding, texturing of titanium occurs and the titanium lattice cell increases in volume, thus inducing internal stresses. Based on these data, it is suggested that the introduction of carbon into the strained titanium particles leads to stacking faults in the titanium hcp lattice, acting as nuclei of fcc titanium carbide in the titanium sites fragmented. Single-crystal TiC 10–20 nm nanoparticles are formed in these sites. The length of titanium–carbon contacts naturally increases with grinding time, giving rise to more nuclei of the new fcc phase. This promotes a mechanically induced self-propagating reaction. The heat generated in the reaction contributes to the sintering of titanium carbide nanoparticles. This results in the formation of particle aggregates 0.1–0.5 μm in size.