Progressive damage behavior of RMI-C/SiC composites under compression based on acoustic emission and in-situ X-ray micro-computed tomography

Abstract

Porosity generated during the fabrication of carbon fiber reinforced silicon carbide composites (C/SiC) significantly reduces their reliability and limits their application. This study investigates C/SiC composites with high densification fabricated via the Reactive Melt Infiltration (RMI) method. The results show that the compressive modulus increases by 68.77 %, indicating significantly enhanced and more stable compressive mechanical performance. The damage evolution mechanisms were thoroughly investigated using acoustic emission (AE) monitoring and in-situ X-ray micro-computed tomography (Micro-CT). The results indicate that C/SiC composites with high densification exhibit a linear–nonlinear–linear mechanical response. The evolution of microcracks primarily influences the mechanical behavior of the material, while the connectivity of different needled fiber regions ultimately leads to quasi-brittle fracture. Therefore, in engineering applications, it is essential to optimize the structural distribution in damage-prone regions and to quantify small-scale damage in order to prevent catastrophic structural failure.