Synchrotron X-ray tomographic characterization of CVI engineered 2D-woven and 3D-braided SiCf/SiC composites

摘要

The properties of ceramic matrix composites strongly depend upon their complex internal structures. To better understand and improve the properties of the silicon carbide fiber-reinforced silicon carbide matrix composites (SiCf/SiC), we explored the microstructural properties of composites reinforced with either two-dimensional (2D) woven or three-dimensional (3D) braided preforms using synchrotron X-ray computed microtomography. Transects and volumetric images of the composites were reconstructed from objection images and the microstructures were investigated in three spatial directions. The network of void space in a composites was visualized in 3D and quantitative analysis of the porosity was performed to characterize the fiber-tissue structures. 2D-woven SiCf/SiC composite exhibited important fluctuations of porosity in different directions and the stacking of plies had a significant effect on the porosity distribution. In contrast, 3D-braided SiCf/SiC composites showed much less variation of porosity. We found the degree of densification of the composite also influenced the porosity distribution. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.