High-performance B4C-TiB2-SiC composites with tuneable properties fabricated by reactive hot pressing

In this work, we systematically studied the effects of powder characteristics (B4C, TiC and Si powders) on the existential form of toughening phases (SiC and TiB2) as well as the overall microstructure and properties of B4C-TiB2-SiC composites fabricated by reactive hot pressing. The particle size of the TiC powder plays a largely determining role in the development of novel toughening phases, the TiB2-SiC composite structure, that are formed in the B4C matrix, while the Si particle size affects the agglomerate level of the SiC phase. The TiB2-SiC composite structure and SiC agglomerates enhance the fracture toughness, but decrease the flexural strength. Both the microstructure and mechanical properties of B4C-TiB2-SiC composites can be effectively tuned by regulating the combinations of the particle sizes of the starting powders. The B4C-TiB2-SiC composites demonstrate flexural strength, fracture toughness and Vickers hardness in the respective range of 567-632 MPa, 5.11-6.38 MPa m(1/2), and 34.8-35.6 GPa.