Fabrication and toughening mechanisms of B4C-SiCf ceramics based on TiB2 interface regulation

The interphase is vital for optimizing the mechanical properties of fiber-reinforced B4C ceramics. In this study, the TiB2 interface composed of one or several layers of fine TiB2 grains was in-situ formed between B4C and SiC fibers by introducing Ti3SiC2-coated SiCf into B4C matrix. The TiB2 interface not only obviously reduced the densification temperature of the B4C ceramics, but also enhanced the mechanical properties. The micromechanics modeling was performed to investigate the weak interphase and thermal residual stress distribution induced by TiB2, where the stress tend to deflect or propagate at the fiber-matrix interface, compared to B4CSiCf ceramics. The particle toughening inside the TiB2 interface layer and stress transfer at the weak interface were identified as the major factors for the improvement of fracture toughness in this system. These results provide valuable guidance for improving the comprehensive performance of B4C-SiCf ceramic composites by interface regulation in future investigations.