Microstructure evolution and phase transformation of TiB₂/SiC/B₄C composites synthesized from Ti-SiC-B₄C ternary system

Bulk TiB₂/SiC/B₄C composites have been synthesized from Ti-SiC-B₄C ternary system with different Ti weight percentages via reactive hot pressing at 1800°C under an applied pressure of 30 MPa for 1.5 h. By Ti amount increasing, the flexural strength curve exhibited an “M-like” tendency reaching the maximum value of 512.36 MPa for 30 wt.% Ti. Microstructural evolution of the composites from conterminously large matrix grains to finely clear-edged particles was observed by scanning electron microscopy. The phase transformation and element diffusion were analyzed by XRD and Energy Disperse Spectroscopy. A hybrid reinforcing mechanism of fracture and crack deflection is proposed to illustrate the change in flexural strength.