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采用单边切口梁法研究了二维碳纤维增强碳化硼–碳化硅复合材料(2D C/(SiC–BxC)n)在空气和真空两种环境下断裂韧性与温度的关系,用扫描电镜观察断口微观形貌。结果表明:真空中2D C/(SiC–BxC)n复合材料的断裂韧性随温度升高而降低,室温下界面结合弱,残余热应力大,易发生纤维桥接裂纹,断裂韧性高;高温下相反。在空气中随温度升高断裂韧性增加,700℃达到最大值,尔后随温度升高而降低,这与生成的B2O3和SiO2.B2O3固溶体会封填裂纹以及碳相的氧化有关。
The relationship between fracture toughness and temperature of two-dimensional carbon fiber reinforced boron carbide-silicon carbide composites (2D C / (SiC-BxC) n) under air and vacuum was studied by unilateral notched beam method. The fracture surface was observed by scanning electron microscopy Micro topography. The results show that the fracture toughness of 2D C / (SiC-BxC) n composite decreases with the increase of temperature, the interfacial bonding is weak at room temperature, the residual thermal stress is large, bridging cracks easily occur and the fracture toughness is high. . The fracture toughness increases with the increase of temperature in air, reaches the maximum at 700 ℃, and then decreases with the increase of temperature. This is related to the formation of cracks and the oxidation of carbon phase in the solid solution of B2O3 and SiO2.B2O3.