This study examines the performance of hybrid sandwich composites with a recycled
aluminium foam (AlF) core and a recycled carbon-reinforced polymer skin layer. Three
composite skin configurations were examined: (i) unidirectional (UD) carbon/epoxy
sheets representing aligned virgin fibre reinforcement, (ii) randomly oriented recycled
carbon fibre (rCF) mats consolidated by hand layup with epoxy, and (iii) randomly
oriented rCF/epoxy sheets consolidated by hot pressing. The AlF core structure analysis
revealed a low density and uniform open-cell structure ideal for lightweight cores.
Comprehensive testing revealed significant performance differences between skin types
and manufacturing methods, underscoring the critical role of processing – particularly
hot pressing – in enhancing fibre compaction, matrix consolidation and interfacial
bonding between the core and facesheets. Unidirectional carbon fibre skins achieved
the highest flexural stiffness. In contrast, hot-pressed rCF mats provided the most
balanced properties, combining high compression, damage resistance, and flexural strength,
due to improved consolidation and reduced porosity in the face sheets. Thus, hybrid
sandwich structures fabricated from recycled AlF core and rCF represent a viable,
environmentally responsible alternative for aerospace, automotive, and protective
applications requiring lightweight, high-strength, and damage-resistant materials.
