Insitu multiscale analysis of fracture mechanisms in nanocomposites

Toughening mechanisms in hard, metal oxide nanoparticle reinforced epoxy systems were analyzed using a multi-scale approach. Samples on varying scales were fabricated using a shear mixing device and the dispersion of the particles was characterized. On the macro-scale, four-point bend testing showed a maximum of an 80% increase in fracture toughness over neat resin samples for composites with low filler volume percents. Novel testing completed within the chamber of a focused ion beam provided insight into the mechanisms of fracture on the microscale, providing validation of the existence of microcracking and crack pinning in the material. Further analysis of the results was coupled with finite element analysis to determine the feasibility of proposed fracture mechanisms, providing insight for the direction of future analysis.