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以碳化硅(SiC)纤维为增强体,采用真空浸渍法制备了2.5维连续SiC纤维增韧的SiO2基(SiCf/SiO2)复合材料,研究了SiC纤维编织体上不同的界面层对SiCf/SiO2复合材料力学性能的影响.化学气相渗透(CVI)法制备的热解碳(PyC)和PyC/SiC双层界面层分别使材料的抗弯强度由无界面层的52.2 MPa提高至67.4 MPa和180.3 MPa,但均使材料的韧性降低.用扫描电镜观察了材料的断口形貌,结果表明,PyC和PyC/SiC层不仅提高了材料的抗弯强度,而且增加了基体同纤维间的结合力,使基体有效地将载荷传递给纤维.PyC/SiC层能有效地保护SiC纤维,防止烧结过程中释放出的结晶水对纤维的损伤,有助于提高材料的力学性能.
A series of SiCf / SiO2 composites were fabricated by vacuum impregnation method using SiC fibers as reinforcement. The SiCf / SiO2 composites reinforced by 2.5-inch continuous SiC fibers were investigated. The mechanical properties of composites were investigated.The flexural strength of PyC and PyC / SiC bilayers prepared by chemical vapor infiltration (CVI) increased the flexural strength of the composites from 52.2 MPa to 67.4 MPa and 180.3 MPa, but all decreased the toughness of the material.The fracture morphology of the material was observed by scanning electron microscopy.The results showed that PyC and PyC / SiC layers not only increased the flexural strength of the material, but also increased the binding force between matrix and fiber, So that the matrix will effectively transfer the load to the fiber.PyC / SiC layer can effectively protect the SiC fiber, to prevent the crystallization of water released during sintering of the fiber damage, help to improve the mechanical properties of the material.