Specimen preparation for transverse modulus measurement of carbon fibres using focused ion beam

Paper in proceeding, 2019

Transverse Young’s modulus of carbon fibres is an important material property for micromechanical modeling and design of carbon fibre reinforced composites. To accurately measure their transverse Young’s modulus is of special importance for applications in novel multifunctional devices, such as structural composite batteries. However, experimental measurement of their transverse Young’s modulus is still largely lacking due to experimental challenges. In this study, we successfully prepared high quality longitudinal cross sections from a commercial carbon fibre using precision ion milling in a combined focused ion beam and scanning electron microscope (FIB/SEM) instrument. These cross sections were then directly used in an atomic force microscope (AFM) and a nanoindentation equipment to measure the transverse Young’s modulus. Here, the entire procedure is described in detail. In particular, the most critical aspects for specimen preparation are identified and discussed.