Mechanical analysis and toughening mechanisms of a multiphase recycled CFRP

The mechanical response of a recycled CFRP is investigated experimentally. A complex multiscale microstructure is revealed, with both dispersed fibres (with fractured-sections) and fibre-bundles. The specific properties of the recyclate compare favourably with those of aluminium and glass-fibre composites. Micromechanical studies show that tensile failure follows the pre-existing fractured-sections on the dispersed-fibres, while compressive failure occurs by shear-banding. Fracture toughness measurements coupled with SEM evidence how bundles considerably toughen the composite by complex failure mechanisms. This analysis can guide the optimisation of recycling processes and support the development of design methods for recycled CFRP; it also provides insight on the mechanical response of other multiphase short-fibre reinforced materials.