Interfacial Mechanics of Copper-Aluminum Composites

Copper–aluminium composites combine the high electrical and thermal conductivity of copper with the low density and corrosion resistance of aluminium, yielding lightweight multifunctional materials for aerospace, electrical contacts, heat exchangers and structural applications. The performance of these bimetal systems is governed by the mechanical, chemical and thermal interactions at the Cu–Al interface, where interdiffusion, phase transformations and residual stresses evolve during fabrication and service. Diffusion across the interface produces sequential layers of intermetallic compounds—predominantly Al₂Cu, AlCu, Al₄Cu₉ and Al₂Cu₃—whose morphology, continuity and thickness depend on processing parameters such as temperature, time and pressure. These intermetallic layers strongly influence bond strength, ductility, electrical conductivity and crack‐propagation behaviour. Mechanical adhesion arises from a combination of metallurgical bonding, micro-interlocking features and compressive residual stresses, all contributing to peel strength and interface toughness. Optimisation of interfacial microstructures requires balancing sufficient metallurgical continuity to transmit load against the avoidance of excessively brittle phases that precipitate delamination. Recent advances in compound casting, laminated architectures and diffusion modelling have clarified the relationships between processing, microstructure and macroscopic performance.

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Interfacial Mechanics of Copper-Aluminum Composites publication trend

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Technical terms

Intermetallic compounds: Ordered phases produced by diffusion between copper and aluminium atoms, often brittle and controlling interface mechanics.

Metallurgical bonding: Adhesion at a solid–solid interface achieved by atomic diffusion and phase formation rather than by mechanical interlocking alone.

Diffusion kinetics: The rate at which atoms migrate across an interface, governing growth rate and sequence of intermetallic layers.

Peel strength: The force required to propagate a crack along a composite interface, indicative of bond integrity.

Delamination: Separation of layers within a composite, often initiated at or near an intermetallic layer by stress concentration.

References

1. Effect of Annealing on the Interface and Mechanical Properties of Cu-Al-Cu Laminated Composite Prepared with Cold Rolling. Materials (2020).
2. The formation and growth of intermetallic compounds during interdiffusion of Al/Cu bimetals. Materials Research Express (2022).
3. Achieving high-strength metallurgical bonding between A356 aluminum and copper through compound casting. Materials Science and Engineering A (2021).
4. Effect of Intermetallic Compound Layer on Peel Strength and Crack Propagation Behavior in Cu/Al/Cu Clad Composites. Metals (2019).