Mechanical behavior of graphene/CoCrFeMnNi high-entropy alloy nanocomposites with Miura origami

Further enhancement in strength and toughness of graphene/high-entropy alloy (HEA) composites is still challenging. This study employs molecular dynamics simulations to compare the tensile behavior of pristine HEA and flat graphene/HEA against Miura-origami (GOri/HEA) and 3D-grid-structured origami (3DGOri/HEA) composites. Results indicate that, compared to flat graphene/HEA, GOri/HEA exhibits 38.18% and 36% enhancements in toughness and ductility. The 3DGOri/HEA composite achieves superior improvements, increasing tensile strength, toughness, and ductility by 44%, 75%, and 30%, respectively. Both origami systems display a distinctive “soft-to-stiff” transition. Mechanistically, the Miura-origami architecture promotes dislocation nucleation near geometric valleys and ridges, effectively mitigating stress concentrations. Furthermore, the study investigates environmental effects, finding that GOri/HEA demonstrates optimal performance at cryogenic temperatures (77 K) and high strain rates (4×10 9 s -1 ). At 77 K, extensive precipitation of body-centered cubic (BCC) phase clusters enhances strain accommodation. Under high strain rates, the proliferation of amorphous phases suppresses shear strain localization, yielding exceptional fracture toughness. These findings offer micromechanical insights for designing advanced composites that balance flexibility and high strength.