Fabrication of В$_4$С/TiB$_2$ composite ceramics using boron carbide reduction

В$_4$С/TiB$_2$ composite ceramics were fabricated by pressing В$_4$С/TiB$_2$ powder mixtures, as well as by reaction pressing. The TiB2 phase content was 10–30 mol.%. It was revealed that increasing the TiB$_2$ additive content reduces open porosity and increases the relative density of composite ceramics. Visual analysis showed that simultaneous boron carbide synthesis and hot pressing makes it possible to obtain a B$_4$C/10 mol.% TiB$_2$ material with uniformly distributed TiB$_2$ grains throughout the B$_4$C phase. The microhardness and fracture toughness of such a material were 41.1 GPa and 4.4 MPa$\cdot$m$^{0.5}$, respectively. The relative density was 99.9%. In the case of hot pressing of a pre-synthesized powder mixture, similar results were achieved with a higher content of the modifying additive, corresponding to 30 mol.% diboride. It has been shown that composite ceramics containing 30 mol.% TiB$_2$ have a higher thermal neutron absorption cross section compared to unmodified ceramics.