Formation of (Ti,V)(C,N) multicomponent solid solutions by high-pressure sintering of mechanically activated Ti-VN-СNT and Ti-VN-Graphite blends

Test samples collected at one-hour intervals during mechanical alloying (MA) of Ti-VN-CNT, Ti-VN-C GR , and Ti-VN-(CNT + C GR ) mixtures in a high-energy planetary ball mill were studied using x-ray diffraction, scanning electron microscopy, and energy-dispersive x-ray spectroscopy. Refinement of the crystal structures of the α -Ti and VN phases revealed that the interaction between the phase components proceeds in two stages during the 8 h milling process. In the first stage, vacancy formation in the VN and α -Ti lattices dominates, leading to the accumulation of metal atom clusters in the reaction zone of the mill. In the second stage, Ti and V atoms embed into the VN and α -Ti structures, respectively, resulting in the formation of V 0.67 Ti 0.33 N and (Ti,V) solid solutions in the mechanically alloyed powders. Raman spectroscopy shows that the interaction between α -Ti and CNTs is accompanied by the formation of TiC carbide. In contrast, the TiC phase was not detected when graphite was used as the initial carbon source. High-pressure high-temperature (HPHT) sintering of the mechanically alloyed Ti-VN-CNT, Ti-VN-C GR , and Ti-VN-(CNT + C GR ) mixtures (7.7 GPa, 2150 °C) results in complete mutual solubility of the constituent phases, leading to the formation of equiatomic (Ti,V)(C,N) solid solutions whose compositions closely correspond to those of the initial mixtures. Overall, the two-step approach (MA followed by HPHT sintering) enabled the synthesis of a multicomponent (Ti,V)(C,N) solid solution in the form of a high-density compact sample with a microhardness of 11.4 ± 1.5 GPa, making it suitable for biomedical applications.