Microstructure, mechanical, thermal, and oxidation properties of a Zr2[Al(Si)]4C5–SiC composite prepared by in situ reaction/hot-pressing

Abstract The microstructure, mechanical and thermal properties, as well as oxidation behavior, of in situ hot-pressed Zr 2 [Al(Si)] 4 C 5 –30 vol.% SiC composite have been characterized. The microstructure is composed of elongated Zr 2 [Al(Si)] 4 C 5 grains and embedded SiC particles. The composite shows superior hardness (Vickers hardness of 16.4 GPa), stiffness (Young's modulus of 386 GPa), strength (bending strength of 353 MPa), and toughness (fracture toughness of 6.62 MPa m 1/2 ) compared to a monolithic Zr 2 [Al(Si)] 4 C 5 ceramic. Stiffness is maintained up to 1600 °C (323 GPa) due to clean grain boundaries with no glassy phase. The composite also exhibits higher specific heat capacity and thermal conductivity as well as better oxidation resistance compared to Zr 2 [Al(Si)] 4 C 5 .