Abstract

Nanostructured TiN/TiB_2/TiSi_2 and TiN/TiB_2/Ti_5Si_2 composite powders have been prepared by mechanochemical reaction from mixtures of Ti, BN, and Si_3N_4 powders. The raw materials have reacted to form a uniform mixture of TiN, TiB_2 and TiSi_2 or Ti_5Si_3 depending on the amount of Si_3N_4 used in the starting mixtures, and the reaction proceeded through so-called mechanically activated self-sustaining reaction (MSR). Fine TiN and TiB_2 crystallites less than a few tens of nanometer were homogeneously dispersed in the amorphous TiSi_2 or Ti_5Si_3 matrix after milling for 12 hours. These amorphous matrices became crystalline phases after annealing at high temperatures as expected, but the original microstructure did not change significantly.

• Keywords: Composite materials;Nanostructured materials;Mechanochemical processing;X-ray diffraction;Transmission electron microscopy;