Microstructure and mechanical properties of B4C-TiB2 ceramic composites hot pressed with in-situ reaction

Ceramic composite materials consisting of a boron carbide (B4C) matrix and titanium diboride (TiB2) secondary phase were in-situ manufactured via chemical reaction of B4C and titanium diboride (TiO2) during hot pressing at a temperature of 1850 degrees C under a pressure of 35 MPa for 60 min in a vacuum atmosphere. The TiO2 addition has a positive effect on both densification of B4C-TiB2 ceramic composites and portion of TiB2 secondary phase. When adding 10 to 50 wt.% TiO2 to B4C, sintered densities increased from 92.1 to 99.5% and portion of TiB2 secondary phase increased from 3.9 to 40.2 vol.%. When increasing the TiB2 portion to its maximal value, the fracture toughness of the composite reached the maximal value of 7.51 MPa.m(1/2). The hardness of B4C-TiB2 composite improved when increasing the portion of TiB2 phase only up to the value of 29.7 vol.% when it reached the average value of 29.8 GPa.