SiC_w/AIN基复合材料增韧机理的微观分析

在 AlN 基体中加入适量的 SiC_w,可以明显地提高其断裂韧性 K_(IC),其它机械性能也有不同程度的改善。SEM,TEM 及 EDAX 微观分析表明,在具有较高 K_(IC)值的 SiC_w/AlN 基复合材料中,SiC_w与AlN 晶粒之间处于较适宜的界面结合,两相之间未发现有明显的界面化学反应。当该复合材料发生断裂时,其内部出现“晶须拔出、裂纹桥连、裂纹偏转”三种增韧机制。

MICROSCOPIC ANALYSIS FOR TOUGHENING MECHANISM IN SiC_w/AIN MATRIX COMPOSITE

Fracture toughness(K_(Ic))and mechanical properties of AIN could be improvedby incorporating certain volumes of SiC_w into AIN matrix.Microscopic analysis by SEM,TEM,and EDAX showed that in the composite with higher fracture toughness,the suitableinterracial bonding existed between SiC_w and AlN grains.No obvious interracial chemical reac-tions between them took place.SiC_w pull-out,crack bridging and crack deflectionsimultaniusly occured in the composite while broken.So 1ts toughening mechanism is the com-plex one consisting of the three mechanisms.