Multicomponent synergistically affected mechanical properties, microstructure, and oxidation resistance of Zr–Al(Si)–C based composites.

Herein, in-situ Zr 3 [Al(Si)] 4 C 6 -based composites with 10–40 vol% ZrB 2 –SiC (2-to-1 molar ratio) were prepared by hot-pressing sintering at 1850 °C. The simultaneously incorporated ZrB 2 –SiC constitute multicomponent reinforcements and has a synergistic effect on the matrix, which improves the sinterability, mechanical properties, and oxidation resistance of materials. It is found that both of the toughness and strength increase first and then decrease with the increasing content of ZrB 2 –SiC, while the hardness increases near linearly. Zr 3 [Al(Si)] 4 C 6 –ZrB 2 –SiC shows high strength (623 MPa), toughness (7.59 MPa m1/2), and hardness (18.6 GPa), which can be ascribed to the synergistic mechanisms of the binary ZrB 2 –SiC including fine-grained strengthening, particle reinforcement, intragranular microstructure, grain's pull-out and crack bridging, etc. In addition, the oxidation kinetics of as-prepared materials follow the parabolic law, and the composite shows a low oxidation rate of 0.87 × 10−5 kg2 m−4 s−1 when oxidized at 1400 °C. [ABSTRACT FROM AUTHOR]