Multiscale analysis of the compressive behaviour of polymer-based composites reinforced by hybrid Al2O3/Al fibres

Metal fibre reinforcements to polymer matrix composites (PMCs) bolster architectural flexibility and functionality affordably but feature a relatively weak interfacial bonding if not surface treated. This work demonstrates that Plasma Electrolytic Oxidation is promising to prepare woven hybrid Al2O3/Al reinforcements for PMCs. The compressive behaviour (a critical design parameter in structural design) of PMCs reinforced by ∼9 to 13 vol% γ-Al2O3/Al fibres with different oxide-to-metal ratios (∼20-50 vol%) is evaluated. The majority of fibres with the oxide ratio of 20% failed in micro-buckling mode at interlacing points. Compared to Al reinforcements, the hybrid Al2O3/Al fibres increased the specific compressive strength (σc/ρ) and modulus (Ec/ρ) of the composite by ∼15% and ∼58%, respectively. Oxide shells thicker than 15-20 μm limited further enhancement due to fibre failure by shear-induced rupture. Thinner shells on Al reinforcements are recommended for PMCs used to manufacture structural components in mechanical engineering applications.