Impact Deformation Characteristics and Mechanism Analysis of Copper–Aluminum Laminated Interface with Wave Impedance Mismatch

The mechanical performance of laminated composites is fundamentally governed by interfacial bonding characteristics and strain transfer efficiency across dissimilar material layers. Conventional approaches to enhance interfacial strength typically rely on chemical composition modifications or postwelding heat treatments, which may compromise the intrinsic properties of constituent materials or induce undesirable intermetallic phases. Here, we demonstrate that explosive welding-induced wavy interfaces with "elephant trunk" morphological features and controlled intermetallic distributions (AlCu/Al₂Cu) can effectively regulate stress redistribution during dynamic loading, without requiring compositional alterations. Through integrated Hopkinson bar experiments and multiscale characterization (XRD/SEM/TEM/CT), we reveal that the strain-rate-dependent deformation disparity between Cu and Al layers generates unique interfacial stress gradients, where dislocation nucleation preferentially initiates in coarse-grained Al regions before propagating across the interface. This strain-mediated interfacial dynamics leads to remarkable energy dissipation capacity. The developed constitutive model quantitatively correlates interfacial microstructure with macroscopic dynamic response, providing a validated framework for designing high-performance laminated structures in electrical/energy applications.