Permanent metal–polymer joints in hybrid lightweight structures hinder reuse and recycling. A design-for-recycling approach is presented for fiber-metal laminates (FMLs) by integrating an activatable thermoset interlayer between the metal sheet and fiber-reinforced polymer (FRP). The interlayer was functionalized with two different blowing-agent systems: the chemical blowing agent azodicarbonamide (ADC) and a physical blowing agent consisting of hydrocarbon-filled microcapsules (VHC). Upon thermal activation, gas generation/expansion induces porosity and microcracking within the interlayer, reduces interfacial integrity, and promotes delamination at the CFRP–thermoset interface, enabling controlled dehybridization and recovery of the constituent material streams.

Laminates were fabricated by hot pressing in a two-stage route. First, the CFRP prepreg was cured in a preceding step to preserve a viable reuse pathway for the composite plies. Second, the cured CFRP was joined to aluminium via the activatable thermoset, which serves as the adhesive. This fabrication strategy simulates end-of-life reuse scenarios, in which reclaimed FRP is available only in the cured state and must be reattached to metal by bonding rather than co-curing. To ensure adequate adhesion, the aluminium surface was laser-textured and the prepreg was pressed with a peel ply to increase surface roughness. The dehybridization concept was assessed by shear-edge tests under both non-activated and thermally activated conditions.

Results show that the baseline interfacial strength is retained in the non-activated state, whereas thermal activation triggers a pronounced loss of interfacial integrity, with ADC enabling near-complete delamination and VHC causing a measurable strength reduction. Overall, the findings demonstrate that activatable, blowing-agent-modified thermoset interlayers provide an effective route to end-of-life separation and material recovery in FMLs.