The mechanical response mechanisms of an AA6061-10Cu hybrid material revealed by experiment-validated and numerical simulations

Based on the unique microstructural features of AA6061-10Cu hybrid materials, this study developed a two-dimensional Representative Volume Element (RVE) model with statistically equivalent features to investigate the influence of Cu particle size and spatial distribution on the mechanical response and fracture behavior of the material under uniaxial tensile loading in different matrix states (as-extruded and T6 heat treated). The RVE simulation was validated by the good agreement between the simulation results and experimental data in terms of mechanical performance and fracture strain. The findings reveal that smaller and more uniformly distributed Cu particles facilitate the formation of continuous load-transfer networks and multiple strain diffusion pathways. In the as-extruded state, the particle network structure effectively suppresses yield localization and enhances capacity for plastic deformation under critical loading conditions. In the T6 heat treated state, the interconnected overlapping stress fields among particles delay the initiation and growth of damage chains, demonstrating superior stress coordination and effective regulation of damage evolution. Moreover, the multiphase synergistic effects induced by the particle network alter the crack propagation path, shifting the fracture mode from rapid and linear failure to a nonlinear damage mechanism involving multi-point initiation and curved propagation, which significantly improves crack propagation resistance and achieves strength-ductility synergy.