Nondestructive Evaluation of the Isolated Pore Spatial Distribution State in a Special-Shaped C/SiC Composite Component.

C/SiC composites are high-temperature structural materials with excellent properties, such as high-temperature resistance and light weight, and are widely used in aerospace fields as advanced materials. Pores are common and unavoidable defects inside composite components, especially affecting mechanical properties and further affecting the safety and life of the components during the service stage. Conventional methods for pore characterization in regular-shaped composites are not suitable for special-shaped C/SiC composite components. To accurately evaluate the effect of pore defects on component properties, in this paper, an effective method is proposed to characterize the spatial distribution state of isolated pores in a special-shaped C/SiC composite component. The isolated pores in the C/SiC composites are identified and localized based on the fractal dimension of local fine characterization of X-ray computed tomography (CT) images using fractal theory. A very strong correlation is found between the fractal dimension of the pore segmentation images and pore characteristics, which is used to identify the connected and isolated pores in C/SiC composites. According to the CT images and fractal dimension statistics analysis results, isolated pores were accurately identified and located. The nondestructive evaluation of isolated pore distribution state inside the studied component was achieved via three-dimensional visual characterization. The minimum volume of the isolated pores identified by the proposed method is 5832 μm³. The results provide a strong basis for further analyzing the effect of pore defect distributions on the mechanical properties of composite components. [ABSTRACT FROM AUTHOR]