Abstract To deeply study the variation mechanisms of mechanical properties, flexural modulus of SiC fibers reinforced SiC matrix (SiC/SiC) composites prepared by conventional and microwave heating at 800 °C–1100 °C was discussed in detail. The elastic modulus of fibers and matrix, interface bonding strength and porosity of SiC/SiC composites were considered together to analyze the changing tendencies and differences in their flexural modulus. The elastic modulus of fiber and matrix was determined by nanoindentation technique and interface characteristics applying fiber push-out test. The porosity and microstructure examinations were characterized by mercury intrusion method, X-ray Diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM). Moreover, two conflicts between the changing trends of elastic modulus and chemical compositions of composite components were focused and explained. Results indicate that three factors played different roles in the flexural modulus of SiC/SiC composites and residual tensile stress in composite components led to the conflicts between their elastic modulus and chemical compositions.

中文翻译：

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微波和常规加热烧结碳化硅/碳化硅复合材料的弯曲模量

摘要 为深入研究力学性能的变化机制，详细讨论了常规加热和微波加热800℃~1100℃制备的SiC纤维增强SiC基（SiC/SiC）复合材料的弯曲模量。结合碳化硅/碳化硅复合材料的纤维和基体弹性模量、界面结合强度和孔隙率，分析其弯曲模量的变化趋势和差异。纤维和基体的弹性模量通过纳米压痕技术和界面特性应用纤维推出试验确定。通过压汞法、X 射线衍射 (XRD)、扫描电子显微镜 (SEM) 和透射电子显微镜 (TEM) 对孔隙率和微观结构进行了表征。而且，聚焦并解释了复合材料部件弹性模量和化学成分变化趋势之间的两个冲突。结果表明，三个因素对 SiC/SiC 复合材料的弯曲模量和复合材料部件的残余拉应力起不同作用，导致其弹性模量和化学成分之间存在冲突。