Cracking detection of unidirectionally reinforced SiC/SiC composite by X-ray Talbot-Lau interferometry

We developed a Talbot-Lau interferometry-based X-ray imaging system with a novel material testing system and studied its feasibility for monitoring the damage evolution process in SiC/SiC composites directly. We tensiletested a polymer-derived unidirectional mini-composite, the specimen was repeatedly loaded and unloaded, the maximum load was successively increased, and images were captured when the specimen was tensed at the maximum load and when released. Unique X-ray images were obtained, and by comparing them with conventional X-ray computed tomography absorption images, we ascertained the advantage of Talbot-Lau interferometry-based X-ray in terms of low-magnification crack detection over very short periods. The results demonstrate that the proposed X-ray interferometry can detect the damage evolution of the composite in the form of randomly initiated transverse cracks in the matrix, even after unloading. These results indicate that Talbot-Lau interferometry-based X-ray imaging is viable as a nondestructive inspection tool for SiC/SiC composites.