This study investigates how Zr doping influences the deformation behavior of Cu-Zr/Al₂Cu/Al composites through molecular dynamics simulations. The impact of Zr content (ranging from 0 to 0.8 wt%) and strain rate on phase evolution, dislocation dynamics, and fracture mechanisms under vertical and horizontal tensile loading was examined. The results indicate that Zr doping achieves a balance between strength and plasticity by means of solute drag, amorphization, and phase competition. At a Zr concentration of 0.2 wt%, the formation of the body-centered cubic (BCC) phase reached a peak (22.04% at ε = 0.11), resulting in a maximum tensile strength of 9.369 GPa while maintaining plasticity due to limited face-centered cubic (FCC) decomposition. A moderate Zr content of 0.6 wt% maximizes strength through amorphization but significantly diminishes plasticity due to excessive FCC-to-BCC transitions. Higher Zr concentrations (0.8 wt%) lead to solute supersaturation, which suppresses phase transitions and slightly reduces toughness by causing hexagonal close-packed (HCP) phase accumulation. The strain rate markedly enhances both strength and plasticity in vertical loading by accelerating dislocation interactions. Vertical tensile deformation initiates brittle fracture, whereas horizontal loading results in ductile failure through sequential load transfer from Al₂Cu layers to Al/Cu interfaces, ultimately causing interfacial decohesion. These findings underscore the essential roles of Zr content and strain rate in modulating phase transformations and interface responses. The research offers a framework for creating gradient Zr-doped or multi-scale composites with optimized strength, plasticity, and damage tolerance suitable for aerospace and electronics applications, where trace Zr additions can reinforce Cu matrices.

This study investigates the cooling process of the Cu/Al₂Cu/Al system following high-temperature diffusion using molecular dynamics (MD) simulations based on an embedded atom method potential. The analysis focused on various characteristics to determine the structural and property changes within the Cu/Al₂Cu/Al system during cooling. The findings reveal that only a small number of Cu atoms diffused along the Z-axis near the Cu/Al₂Cu interface, while significant diffusion of Al atoms occurs in all directions at the Al/Al₂Cu interface. Moreover, 673 K is identified as a crucial temperature for the crystal transformation of the Cu/Al₂Cu/Al system during cooling. The Cu/Al₂Cu interface exhibited migration behavior along the positive Z-axis. Additionally, the growth of Al₂Cu towards the Al side resulted in a symmetrical lattice distribution along the Al/Al₂Cu interface, leading to the formation of a twin crystal. In the AI layer, locally disordered atoms transform into vacancies under stress, accumulating as the temperature drops, thereby providing favorable conditions for dislocation initiation. Notably, cooling of the Al layer to 650 K led to the initial generation of 1/6 Shockley incomplete dislocations.