Mechanical and thermal physical properties, and thermal shock behavior of (ZrB₂+ SiC) reinforced Zr₃[Al(Si)]₄C₆composite prepared by in situ hot-pressing

The mechanical and thermal physical properties, as well as thermal shock behavior of in situ hot-pressed 30 vol.% (ZrB₂+ SiC)/Zr₃[Al(Si)]₄C₆composite have been investigated and compared with monolithic Zr₃[Al(Si)]₄C₆ceramic. The composite shows superior hardness (Vickers hardness of 17.5 GPa), stiffness (Young's modulus of 418 GPa), strength (room-temperature bending strength of 648 MPa, and high-temperature bending strength of 439 MPa at 1300 °C in air), and toughness (fracture toughness of 7.69 MPa m^1/2) compared with Zr₃[Al(Si)]₄C₆. The composite can retain a high modulus of 362 GPa at 1350 °C (87% of that at ambient temperature). In addition, the composite exhibits higher specific heat capacity and thermal conductivity but slightly lower coefficient of thermal expansion compared with Zr₃[Al(Si)]₄C₆. The critical thermal shock temperature difference (ΔT_c) increases from 225 °C for Zr₃[Al(Si)]₄C₆to 345 °C for the composite, and the calculation results of thermal shock resistance parameters also indicate a much improved thermal shock resistance of the composite.