氧化物陶瓷基复合材料中晶须／基体界面的特性及作用

Characteristics and Effects of Whisker/Matrix Interfaces in Oxide Ceramic Composites

本文研究了ＳｉＣ晶须增韧氧化物陶瓷基复合材料中的晶须／基体界面结构性质及其在补强增初作用中的作用机制．ＴＥＭ观察结果表明：复合材料中的ＳｉＣｗ／Ａｌ２Ｏ３、ＳｉＣｗ／ＺｒＯ２（２Ｙ）和ＳｉＣｗ／ＺｒＯ２（６Ｙ）界面结合致密，在分析电镜下未发现明显的界面过渡层或界面相．由于膨胀失配而受拉应力作用的界面基体一侧往往成为微裂纹形核的有利部位，ＺｒＯ２中ｔ－ｍ相变的体积膨胀效应可以部分抵消这种热应力，调整基体的受力状态，从而使ＳｉＣｗ／基体的界面结合强度提高，微裂纹数量减少．ＳｉＣｗ对氧化物陶瓷的强韧化效果决定于ＳｉＣｗ／基体界面的结构性质．

The characteristics of whisker/matrix interfaces and their effects on the reinforcing and toughening mechanisms in the SiC whisker reinforced oxide ceramic composites were studied in this paper. TEM examinations show that the SiCw/Al2O3, SiCw/ZrO2(2Y) and SiCw/ZrO2(6Y) interfaCes in the composites are bonded tightly and no obvious intermediate layers or second phases can be observed under analytical TEM. The tensile stress developed in the matrix due to incompatibility of thermal tensile stress can be partially canceled out by volume expansion effect of t-m transformation of ZrO2 so that the bonding of SiCw/matrir interface can be improved to some extent and the numbers and sizes of microcraks are decreased. The effects of SiC whisker strengthening and toughening oxide ceramics are dependent on the characteristics of SiCw/matris interfaces.