Bulk TiB(2)-Based Ceramic Composites with Improved Mechanical Property Using Fe–Ni–Ti–Al as a Sintering Aid

The densification behavior, microstructure and mechanical properties of bulk TiB(2)-based ceramic composites, fabricated using the spark plasma sintering (SPS) technique with elements of (Fe–Ni–Ti–Al) sinter-aid were investigated. Comparing the change of shrinkage displacement of pure TiB(2) and TiB(2)–5 wt% (Fe–Ni–Ti–Al), the addition of elements Fe–Ni–Ti–Al into TiB(2) can facilitate sintering of the TiB(2) ceramics. As the sintering temperature exceeds 1300 °C, the relative density does not significantly change. Alumina particles and austenite (Fe–Ni–Ti) metallic binder distributed homogeneously in the grain boundary of TiB(2) can inhibit the growth of the TiB(2) grains when the sintering temperature is below 1300 °C. The density and particle size of TiB(2) greatly influence the mechanical behavior of TiB(2)–5 wt% (Fe–Ni–Ti–Al) composites. The specimen sintered at 1300 has the highest microhardness of 21.1 ± 0.1 GPa with an elastic modulus of 461.4 GPa. The content of secondary borides (M(2)B, being M = Fe, Ni), which are more brittle than TiB(2) particles, can also influence the fracture toughness. The specimen sintered at 1500 °C has the highest fracture toughness of 6.16 ± 0.30 MPa·m(1/2) with the smallest M(2)B phase. The results obtained provide insight into fabrication of ceramic composites with improved mechanical property.