Three-dimensional reconstruction of resin-infused carbon fiber reinforced polymer composite

The study of the microstructure of carbon fiber reinforced polymer (CFRP) composites typically involves optical microscopy observations of the samples in two-dimensions (2D), and any threedimensional (3D) characteristics of the composites are generally inferred from these planar observations. In order to properly understand the layout and dispersion of the fibers in this composite, 3D observations are necessary. In this work, serial sectioning and 3D reconstruction methods were employed to generate 3D views of resin-infused CFRP composite samples. Serial sectioning tasks were performed using metallography techniques and equipment, where images of the composite were obtained after each successive polishing step. Using the open source software NIH ImageJ, these images were then digitally enhanced and combined to generate a 3D volume of the composite. The 3D reconstructions clearly showed that the fiber and tow bundles, which were expected to be straight and parallel, were dispersed and undulating. The resultant 3D microstructure revealed resin-rich areas that may weaken the composite due to lack of reinforcements in this area. On the other hand, the measurements of fiber undulation showed that the inclination angles were generally less than 1° which would not significantly weaken the CFRP further.