A novel optical technique for observation of global particle distribution in toughened composites

One promising approach to improving fracture toughness is interleaved toughening. Past observations of toughened particles have typically been conducted using the optical microscope; however, such an approach may not be able to provide a 3-D, birds-eye view of how the toughened particles are distributed on a composite interlaminar surface. In this paper, we developed a simple yet novel optical technique for observing global particle distribution on a composite laminate surface. IM7/8551-7, a material used for the fan blades of the GE90, the world’s most powerful commercial aircraft jet engine, was used to demonstrate the strength of our optical technique, which produces high-quality morphological information. High-GIC laminate had more uniform and denser particle distribution with a smaller particle size, whereas low-GIC laminate had larger, but far less toughened particles. The same optical technique can also be used on other particle-toughened composite systems.