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

A water-quenching technique was adopted to evaluate the thermal shock behavior of monolithic Zr-3[Al(Si)](4)C-6 ceramic and in situ 30 vol.% (ZrB2 + ZrC)/Zr-3[Al(Si)]4C6 composite in air. The strength retention of specimens was measured after varying temperature difference up to 800 degrees C. The critical thermal shock temperature difference (Delta T-c) increases from 225 degrees C for Zr-3[Al(Si)](4)C-6 to 330 degrees 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 Zr-3[Al(Si](4)C-6, 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. (C) 2014 Elsevier B.V. All rights reserved.