Rare-earth Y 2 O 3 modified interfaces for enhanced adhesion and fracture resistance in hybrid titanium fiber–metal laminates

This study examines the effect of rare-earth Y2O3 nanoparticle modification on adhesion-controlled interfacial performance and fracture behavior of hybrid titanium/carbon–basalt fiber metal laminates fabricated by compression molding. Emphasis is placed on tailoring the metal–polymer interface through controlled nanofiller incorporation to improve interfacial cohesion and crack resistance. Laminates containing 0–2.0 wt.% Y2O3 were produced using a symmetric stacking configuration and a two-stage curing cycle under constant consolidation pressure. Adhesion-related performance was evaluated through peel testing and Mode-I fracture toughness measurements, supported by tensile, flexural, and impact tests, along with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses to elucidate interfacial damage mechanisms. An optimal Y2O3 content of 1.0 wt.% resulted in marked enhancement in peel resistance, impact energy absorption, and Mode-I fracture toughness, with the fracture resistance at 0.2-mm crack extension (J0.2) and critical J-integral fracture toughness (JIC) approaching ∼40 kJ m−2. Fractographic observations reveal a transition from interfacial debonding-dominated failure to stable crack growth characterized by adhesive retention, fiber bridging, and constrained matrix deformation. At higher nanofiller contents, particle agglomeration disrupted resin continuity, leading to reduced interfacial integrity and more brittle fracture. The results demonstrate that rare-earth oxide nanomodification provides an effective route for adhesion-driven interface engineering in titanium-based fiber–metal laminates, offering improved interfacial reliability and fracture resistance relevant to bonded structural systems.