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 ∼9–13 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 (σ_c/ρ) and modulus (E_c/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.