Toughening mechanism and thermal shock resistance of ZrO_2 (3Y)/Fe28at-%Al composites evaluated by indentation techniques

摘要

Toughening mechanism and thermal shock resistance of monoclinic ZrO_2 (3Y) and ZrO_2 (3Y)/ Fe28at-%AI composites were investigated by indentation techniques. ZrO_2 (3Y)/Fe28at-%AI composites exhibited more pronounced R curve behaviour than the monolithic ZrO_2 (3Y). Quantitative analysis of toughening behaviour indicated that the enhanced toughness was attributed to the synergistic effect between crack bridging toughening and phase transformation toughening. Thermal shock resistance of as prepared composite was evaluated by indentation-quench method. Compared with monoclinic ZrO_2 (3Y), ZrO_2 (3Y)/Fe28at-%AI composites had higher critical thermal shock temperature difference ΔT_U at which cracks grow unstably. The thermal shock resistance parameters R, R' and R"" were also calculated to evaluate the thermal shock resistance. It was found that the addition of Fe28at-%AI particles could lead to higher K_(IC), thermal conductivity and lower Yong's modulus, thus resulting in higher ΔT_U values of ZrO_2 (3Y)/ Fe28at-%AI composites than monocline ZrO_2 (3Y).