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采用直流电热化学气相沉积(CVD)法制备出高强度SiC纤维(W芯),采用拉伸试验、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等对SiC纤维的强度、相组成、断口特征及微观结构进行了分析。结果表明,CVD-SiC纤维主要由β-SiC组成;制备过程中W芯同SiC发生化学反应,产生厚度约300nm的界面反应层,且反应层处存在着较大的残余拉应力;高强度SiC纤维裂纹产生于W/SiC界面反应层处,而低强度SiC纤维的裂纹源多处于W芯内部或纤维表面。
High-strength SiC fibers (W core) were prepared by direct current thermal chemical vapor deposition (CVD). The tensile strength, the tensile strength and the tensile strength of SiC fibers were studied by tensile test, XRD, SEM and TEM. , Phase composition, fracture characteristics and microstructure were analyzed. The results show that the CVD-SiC fibers mainly consist of β-SiC. During the preparation process, the W core reacts with SiC to produce an interface reaction layer with a thickness of about 300 nm and a large residual tensile stress at the reaction layer. High-strength SiC Fiber cracks originate at the W / SiC interface reaction layer, whereas cracks in low-strength SiC fibers are mostly located inside the W core or on the surface of the fiber.