Tuning the strength–plasticity synergy mechanism in multilayered AlxCoCrFeNi/CoCrFeNi HEAs via layer number and Al content: A molecular dynamics study

To achieve the synergistic optimization of strength and plasticity for AlxCoCrFeNi/CoCrFeNi multilayered high-entropy alloys (HEAs), this study employed molecular dynamics simulations to systematically investigate the effects of layer number (3, 5, 7, and 9 layers) and Al content (x = 0.3, 0.6, 0.9) on their mechanical properties and deformation mechanisms. The results show that the 7-layer Al0.6CoCrFeNi/CoCrFeNi model exhibits the optimal comprehensive performance, with tensile strength of 857.20 MPa and elongation of 9.40%. Its performance advantage stems from the synergy between Taylor hardening and heterogeneous deformation induced strengthening. Microscopic analysis reveals that during tensile deformation, random dislocation nucleation in the 7-layer model promotes the “growth-merging” of the hexagonal close-packed (HCP) phase and uniform strain distribution; in contrast, interface-preferential dislocation nucleation in models with other layer numbers induces the “splitting-migration” of the HCP phase and strain localization. This study clarifies the regulatory role of the coupling effect between composition and interface structure on the deformation behavior of layered HEAs, providing a theoretical basis for the design of high-performance multilayered metallic materials.