多元体系A2IO3陶瓷复合材料的力学性质研究

MECHANICAL PROPERTIES OF UNSTABILIZED ZrO_2 TOUGHENED-SiCw REENFORCED-Al_2O_3 CERAMIC COMPOSITES

The comparisions of mechanical properties of the unstabilized ZrO2-toughened Al2O3 and the SiCw-reinforced Al2O3 with those of the ZrO2-toughened and SiCw-rein-forced Al2O3 ceramic composites have been investigated. Experimental results show that the unstabilized ZrO2 greatly increases the facture toughness of Al2O3 ceramics, but largely degrades its elastic modulus, fracture stregnth and Vicker's hardness. Although the mechanical properties of SiCw-reinforced Al2O3 composites have been enhanced,they are limited very much because of the decrease of relative density resulted from the addition of SiC wiskers. However, not only the advantages of above both are remained, but also fracture toughness can be further enhanced by the combining toughening and reinforcing of unstabilized ZrO2 and SiC whiskers. It may be considered as the results of the combination of grain refinement and mi-crocrack toughening of ZrO2 as well as higher elastic modulus, deviding load, bridging and deflecting crack, and pull-out effects of whiskers. The fracture toughness and flexural strength of 75vol%(Al2O3-20vol%ZrO2) 25vol%S1Cw composite measured in the room temperature are as high as 11.72 MPam1/2 and 376MPa respectively.