The thermal shock behavior of Zr₃[Al(Si)]₄C ₆ and in situ (ZrB₂ + ZrC)/Zr₃[Al(Si)] ₄C₆ composite

A water-quenching technique was adopted to evaluate the thermal shock behavior of monolithic Zr₃[Al(Si)]₄C₆ ceramic and in situ 30 vol.% (ZrB₂ + ZrC)/Zr₃[Al(Si)] ₄C₆ composite in air. The strength retention of specimens was measured after varying temperature difference up to 800 °C. The critical thermal shock temperature difference (ΔT_c) increases from 225°C for Zr₃[Al(Si)]₄C₆ to 330°C for the composite. The calculation results also indicate a much higher thermal stress fracture resistance parameter (R), thermal stress damage resistance parameter (R^IV), and thermal stress crack stability parameter (R _st) for the composite. Compared with Zr₃[Al(Si)] ₄C₆, the significantly improved thermal shock resistance of the composite should be attributed to the increase in thermal conductivity and the significant strengthening and toughening effect such as particulate reinforcement, grain's pull-out, crack bridging, deflection and branching, and microcracks derived by the in situ incorporation of ZrB₂ and ZrC.