Mechanical and thermal physical properties, and thermal shock behavior of (ZrB2 + SiC) reinforced Zr3[Al(Si)]4C6 composite prepared by in situ hot-pressing

Abstract

The mechanical and thermal physical properties, as well as thermal shock behavior of in situ hot-pressed 30vol.% (ZrB2+SiC)/Zr3[Al(Si)]4C6 composite have been investigated and compared with monolithic Zr3[Al(Si)]4C6 ceramic. The composite shows superior hardness (Vickers hardness of 17.5GPa), stiffness (Young’s modulus of 418GPa), strength (room-temperature bending strength of 648MPa, and high-temperature bending strength of 439MPa at 1300°C in air), and toughness (fracture toughness of 7.69MPam1/2) compared with Zr3[Al(Si)]4C6. The composite can retain a high modulus of 362GPa 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 (ΔTc) increases from 225°C for Zr3[Al(Si)]4C6 to 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.