Abstract: The thermal shock resistance of Al₂O₃/TiC(AT) and cobalt-coated Al₂O₃/TiC(ATC) composites was measured by the indentation-quench technique. The experimental results show that cobalt-coated Al₂O₃/TiC composites exhibit better crack extension resistance and cyclic thermal shock resistance than Al₂O₃/TiC, and the critical temperature difference for ATC composites improved 25℃ compared with that of the AT composites. Calculated results of thermal shock resistance parameters R , R', R^IV and R_st show that both the resistance to thermal shock fracture and thermal shock damage of ATC composites are better than those of AT. The thermal physic parameters are changed very little but the flexure strength and fracture toughness of ATC composites are improved greatly by introducing 3.96vol％ cobalt into AT composites using an electroless method, which contribute to the higher thermal shock parameters. In a word, the better thermal shock resistance should be attributed to the higher flexure strength and fracture toughness of ATC.

Key words: indentation-quench, thermal shock resistance, cobalt-coated Al2O3/TiC composites, thermal shock resistance parameters