Key factors for achieving synergistic improvement of strength and toughness in ZrC_w/ZrB₂-SiC Composites:Whisker Integrity, Density, and the toughening mechanism

In this study, self-developed ZrC whiskers were used as reinforcements for ZrB₂-SiC ceramics. A novel two-step ball milling method was proposed and determined to more conducive to achieving uniform mixing and reducing the damage to the whiskers. Grain erosion during sintering can damage the integrity of whiskers, which has a significant impact on the mechanical properties. The whisker integrity is mainly affected by the sintering temperature and whisker diameter. The tape casting process has been successfully used to improve the density of composites. Finally, the strength and toughness can reach up to 731.8 ± 47.1 MPa and 8.97 ± 0.41 MPa·m¹/², respectively. The results of the micro-nano mechanics tests show that the strength and fracture energy of the whiskers are much greater than those of the matrix and the interface, which enables the whiskers play an important reinforcing role. For composites with strong bonding, crack deflection and whisker pull-out in non-vertical directions are the main toughening mechanisms. This work not only innovates the preparation process of ZrC_w/ZrB₂-SiC composites, but also deepens the research on the toughening mechanism of composites with strong interfacial bonding. This work may provide process reference and theoretical basis for the preparation of high-performance whisker-reinforced ceramic matrix composites.