The properties of CVD silicon carbide (SiC) fiber are closely correlated with its complex microstructure; however, the microstructural architectures contributing to its strength are not well understood. Here, two kinds of W-core SiC fibers (SiC-3200 and SiC-3800) coated with same C coating, possessing different tensile strength and discrepant microstructure in SiC portion, were fabricated by controlling deposition temperature during CVD process. The structure discrepancy contributing to the different tensile strength for both SiC fibers were explored by the combined Raman spectra, EPMA, SEM and HRTEM. It is revealed the high-crystallinity β-SiC columnar grains in the inner zone always evolve into a higher disorder character yet involving partial surviving columnar grains toward surface for both SiC fibers. However, as compared with SiC-3800 fiber, the slightly higher C over-stoichiometric composition yields lower-crystallinity SiC columnar grains across the radius for SiC-3200 fiber, further resulting in lower strength via forming smoother stepped fracture morphology.

CVD碳化硅（SiC）纤维的性能与其复杂的微观结构密切相关。然而，对其强度做出贡献的微结构架构尚不十分清楚。在这里，通过控制CVD过程中的沉积温度，制造了两种涂有相同C涂层的W芯SiC纤维（SiC-3200和SiC-3800），它们具有不同的拉伸强度和不同的SiC组织微观结构。通过组合拉曼光谱，EPMA，SEM和HRTEM探索了导致两种SiC纤维具有不同拉伸强度的结构差异。揭示了内部区域中的高结晶度β-SiC柱状晶粒始终演变为更高的无序特征，但涉及到两种SiC纤维的部分残留的柱状晶粒朝向表面。但是，与SiC-3800光纤相比，