C/C复合材料孔隙分形表征与弯曲强度计算

Pore Fractal Characterization and Calculation of Flexural Strength of Carbon/Carbon Composites

采用热梯度化学气相渗透工艺(TCVI)制备了11组不同表观密度的热解碳基C/C复合材料,从每组C/C复合材料上分别截取4个试样进行弯曲强度实验。采用偏光显微镜(PLM)分析了材料的孔隙结构,并利用计盒法求出了图像中孔隙的分形维数。在此基础上利用分形理论表征C/C复合材料的孔隙结构,建立了相同增强预制体及致密化方法制备的C/C复合材料的弯曲强度分形计算模型。计算结果与实验值吻合较好,表明本研究提出的模型具有可行性。

A group of samples with different apparent density were prepared by thermal gradient chemical vapor infiltration （TCVI） in order to study the fractal feature of pore structure in C/C composites. It measures bending strength using four samples in each group, and gets the fractal dimension of pore structure by means of polarized light microscope （PLM）, in accordance with box-counting method, which can achieve the characterization of pore structure in C/C composites based on fractal theory. Finally, a prediction model of bending strength is built applying to C/C composites with the same perform and densification method. Moreover, the results of bending strength experiment verify the feasibility of the model.