Direct 3D microscale imaging of carbon-carbon composites with computed holotomography

摘要

As part of the modelling of chemical vapor infiltration, one of the processing techniques of carbon-carbon composites, a better understanding of the relation between fiber architecture and transport properties is required. An excellent starting point for the pore-scale modeling of heat and gas transport is the acquisition of 3D images of the porous media through computed microtomography at various densification stages. Due to the low X-ray absorption rate of light materials such as carbon, a poor image contrast is obtained with absorption tomography. On the other hand, phase contrast imaging is readily feasible using the coherence properties of modern synchrotron beams. Holotomography has been performed on these materials and it provides quantitative density images where fibers and pyrocarbon matrix deposit are easily distinguishable. Such images are appropriate for the pore-scale computation of many effective transport properties.