C-C-SiC复合材料的制备及其层间剪切强度分析
Preparation and Analysis of Interlaminar Shear Strength of C-C-SiC Composite
曹晓雨，张程煜，殷小玮，刘建功
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作者单位：西北工业大学 超高温结构复合材料重点实验室
中文关键字：液硅渗透；C/C-SiC；剪切强度
英文关键字：LSI；C/C-SiC；Shear strength
中文摘要：采用先驱体浸渍裂解结合液硅渗透的方法制备C/C-SiC复合材料。通过X射线衍射和扫描电镜分析了材料的成分和微结构，采用压缩双切口试样法分别在室温和1600 C下测试其层间剪切强度，分析了微观剪切破坏机理。结果表明：碳纤维表面的热解碳(PyC)与液硅反应生成一层SiC，保护纤维不受残余Si的损伤。树脂碳和液硅反应生成的SiC填充了多孔C/C的孔隙。材料的高温层间剪切强度是室温下的两倍左右。室温下基体存在残余热应力，界面结合强度低，材料属于脆性断裂，高温下基体残余热应力得到释放，界面结合强度增大，基体裂纹部分闭合，复合材料可承受更大剪切应力。
英文摘要：C/C-SiC composite was prepared by polymer infiltration and pyrolysis and liquid silicon infiltration (LSI). The composition and microstructure of the composite were analyzed by X-ray diffraction and scanning electron microscopy. The interlaminar shear strength (ILSS) of the composite was tested by compression of double-notched specimen at room temperature and 1600C. The shear damages were investigated to understand the microscopic mechanisms. The results show that, a layer of SiC forms around the C fiber by the reaction of pyrolysis carbon(PyC) and liquid Si, which protects the carbon fibers from damages of excessive Si. SiC caused by the reaction of resin C and liquid Si fills the pores in the C/C composite. ILSS of the composite at elevated temperature is about twice than that at room temperature. The matrix fractures in a brittle manner due to the residual thermal stress and low interface bonding strength, whereas, the material can bear bigger shear stress due to the remission of the residual thermal stress，high interface bonding strength and partly healing of matrix crack at elevated temperature.