含强约束界面相共晶复合陶瓷的有效热膨胀系数

Thermal Expansion Coefficient of Eutectic Composite Ceramic with Strong Constraining Interphase

基于共晶复合陶瓷的细观结构特点,建立了含夹杂、强约束界面相、基体氛围和有效介质的四相模型;借助复合材料有效热膨胀系数的稀疏解,确定了棒状共晶体内的有效热应力场和两个热膨胀系数的解析表达式;将棒状共晶体看作具有随机方位的横观各向同性夹杂,将棒状共晶体边界处的基体颗粒看作球形的各向同性夹杂,对含强约束界面相共晶复合陶瓷的有效热膨胀系数进行了预报。结果表明共晶复合陶瓷的有效热膨胀系数具有明显的尺度效应。

On the basis of microstructures in eutectic composite ceramic with strong constraining interphase,a four phase model was put forward, which was composed of inclusion, strong constraining interphase, matrix--atmosphere and effective medium. In view of the thermal expansion coefficient of composite containing scattered inclusions, the two effective thermal expansion coefficients of rod--shaped oxide eutectic ceramics were determined. Finally, regarding the rod--shaped oxide eutec- tic ceramic and matrix particle as a transverse isotropy inclusion and isotropy inclusion, the effective thermal expansion coefficient of eutectic composite ceramic with strong constraining interphase was predicted. The results show that the effective thermal expansion coefficient has obvious size dependence.