Crystallographic Features of the Formation of Nanodispersed Titanium Carbide during Grinding of Titanium and Carbon in a Planetary Mill

Abstract

Structural changes of titanium during grinding of the titanium and carbon powder mixture in a АIR-015М planetary mill are studied. It is established, that during grinding of the mixture of titanium and carbon powders, nanocrystal titanium carbide single crystals with particles 7–50 nm in size are formed in the volume of the reaction zone. It is found, that texturing of titaniumoccurs at the initial stage of grinding. Also, the cell of titanium lattice increases in volume and stresses occur herein. Based on these data, it is suggested that the introduction of carbon into the strained titanium particles can lead to the defects in hexagonal dense packing, which act as FCC-nuclei of titanium carbide in the titanium sites fragmented. Single-crystal TіC nanoparticles 10–20 nm in size are formed in these sites. The length of titanium–carbon contacts naturally increases with increasing grinding time and leads to an increased number of new FCC phase nuclei. This promotes a mechanically induced self-propagating reaction. The heat generated during the reaction contributes to the sintering of titanium carbide nanoparticles. This leads to the formation of particle aggregates 0.1–0.5 µm in size.