Dual-Mode Nondestructive Uniformity Characterization of Special-Shaped Ceramic Matrix Composites

Abstract

Ceramic matrix composites represent a novel type of high-temperature structural material. Defects such as porosity, delamination, and cracking generated during the fabrication process significantly impact the structural uniformity and performance, especially in the case of irregular shapes where this issue becomes more pronounced. Conventional methods that rely on overall grayscale values often fail to quantify structural density differences in irregular components. To address this, we propose a dual-mode uniformity characterization method based on block grayscale difference calculation. Considering the high porosity of ceramic matrix composites and the characteristics of pore defects, the tomography image after pore removal is obtained based on the adaptive threshold algorithm. These images are then partitioned into blocks based on their spatial positions, and the average grayscale values of each block are calculated to achieve a digital representation of the composite material’s uniformity. Furthermore, three-dimensional reconstruction of the average grayscale using volume rendering algorithms provides a visual representation of the structural distribution for intuitive analysis. Test analysis of a U-shaped C_f/SiC specimen yielded maximum grayscale values for blocks of 134.81, minimum grayscale values of 92.24, and grayscale differences between blocks of 42.57, effectively characterizing the digital differences in structural uniformity among various blocks of the specimen. The visualization results of three-dimensional reconstruction and color mapping depict the spatial distribution characteristics of the structural specimen. This method offers a new approach to characterizing the uniformity of irregular-shaped ceramic matrix composites.