热处理对W芯SiC纤维结构和力学性能的影响

Scanning electron microscope (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), Raman spectrometer analysis and tensile test were employed to study the microstructure of the components in W-core SiC filaments and its mechanical properties after different heat treatments in a low vacuum environment. The results show that the tensile strength of the W-core is much higher than that of the W-core SiC filaments after experiencing the same heat treatment. The structural stability of the W/SiC interfacial reaction layer and the SiC deposit can be well retained after heating at 800 ℃ for 50 h, which enables the tensile strength of the W-core SiC filaments to reach 3.10 GPa. Further increasing the temperature during the heat treatment not only promotes the growth of the W/SiC interfacial reaction layer as well as the interfacial voids, but also severely damages structural stability of the SiC deposit through the coarsening of the interior columnar grains and the formation of grooves on the surface, which leads to the Weibull modulus of W-core SiC filaments after heating at 900 ℃ for 50 h and the tensile strength after heating at 1000 ℃ for 50 h decrease to 9.7 and 1.12 GPa, respectively.