Development of a lab-based In situ XCT oven for vacuum-bag processing of prepreg laminates

Real-time 3D microstructure changes in prepreg laminates during curing was observed using widely available X-ray Computed Tomography (XCT) hardware at high temporal resolution (2 min) and spatial resolution (25 µm voxel size). The methodology was demonstrated in a cylindrical convection oven with an internal diameter of 100 mm, a heating rate of 2°C/min, a maximum operating temperature of 135°C, and an integrated vacuum line. The technique was applied to three representative carbon fibre reinforced epoxy prepreg samples having flat, tapered and corner geometries. The increasingly complex geometries lead to higher void mobility and thickness changes that were captured in 40-50 mm size samples. Image processing of the XCT data was enhanced by the use of deep learning semantic segmentation for feature extraction. Uninterrupted microstructure evolution was visualised in larger samples and more realistic processing conditions than previous lab-based In Situ XCT studies.