TiB2-reinforced B4C composites produced by reaction sintering at high-pressure and high temperature

ABSTRACT

Obtaining both high hardness and toughness is a challenge in B₄C-nano-adhesive composites. Solving the inhomogeneous distribution of nano-adhesives in B₄C and forming the chemical bonding at grain boundary is an effective method. Here, we reported that the uniform distribution of titanium diboride (TiB₂)-reinforced B₄C composites synthesized by high-pressure and high temperature (HPHT). It is found that HPHT sintering can effectively inhibit the grain growth and increase the relative density. Moreover, HPHT sintering can cross high reaction energy barrier and effectively promote the formation of chemical bonding at grain boundary between B₄C and TiB₂. The optimal hardness and toughness value reach 30.0?±?0.9?GPa and 7.87?MPa·m^1/2, respectively. The improvement of hardness and toughness in the final products are ascribed to the strengthening of nanoTiB₂ connection of B₄C boundary and intergranular fracture mechanism. This work suggests a new way to achieve the uniform distribution of nanoTiB₂ in B₄C and form the chemical bonding at grain boundary, which is of great significance to the further development of TiB₂-reinforced B₄C composites with excellent mechanical properties.