Mechanical properties of graphite flakes and spherulites measured by nanoindentation

The mechanical properties of graphite flakes and spherulites in cast iron were measured by nanoindentation. The spherulites had a significantly lower Young’s modulus and hardness than the graphite flakes. This was attributed to the faulty growth morphology and the presence of foreign particles (impurities) in the spherulites as detected in the micro Raman spectroscopy and confirmed by the different deformation behaviours of the flakes and spherulites.