Al_2O_3和Sialon陶瓷中LiTaO_3第二相的断裂行为

Fracture Behavior of LiTaO_3 Phase Dispersed in Al_2O_3 and Sialon Ceramics

将LiTaO3压电陶瓷颗粒分别添加到Al2O3和Sialon结构陶瓷基体中,通过对复相陶瓷试样断口形貌和裂纹扩展路径的观察,研究了Al2O3和Sialon结构陶瓷基体中LiTaO3第二相的断裂行为。研究结果表明:Al2O3和Sialon陶瓷基体的断裂均为沿晶断裂,LiTaO3压电陶瓷颗粒的断裂为穿晶断裂,在LiTaO3第二相的断口上,观察到了许多断裂台阶,这些断裂台阶是由于试样断裂时,裂纹扩展过程中遇到LiTaO3晶粒内的90°电畴发生裂纹偏转和分支引起的。

LiTaO3 piezoelectric phase was introduced into Al2O3 and Sialon structural ceramics, respectively. The fracture behavior of LiTaO3 piezoelectric phase in Al2O3 and Sialon structural ceramics was studied by the observation of the fracture surface and crack paths of the composite ceramics. The results showed that the fracture of Al2O3 and Sialon matrix was intergranular fracture. While the fracture of LiTaO3 piezoelectric phase was transgranular fracture. Many steps were observed on the fracture surface of LiTaO3 grains. These steps were caused by crack deflection and branching at 90° domain boundaries in LiTaO3 grain.