High-throughput screening and Cu-content-driven optimization of properties in Cux(CoCrFeNi)100-x high-entropy alloys

Optimizing the balance between mechanical and electrical properties remains a critical challenge for Cu-containing high-entropy alloys (HEAs), due to the complex and often competing effects of Cu on microstructure and deformation behavior. In this work, a high-throughput film screening strategy was employed to systematically investigate the influence of Cu content on the microstructure, mechanical properties, and electrical resistivity of Cu x (CoCrFeNi) 100-x HEAs over a wide compositional range. The film results reveal that Cu content plays a dominant role in regulating grain morphology, lattice distortion, nano-hardness, and electrical resistivity, with several non-monotonic responses indicating distinct transition regimes. Based on these composition-driven trends, five representative compositions spanning Cu-poor, intermediate, and Cu-rich regimes were selected for bulk alloy fabrication to further evaluate mechanical strength, ductility, and wear resistance under realistic solidification conditions. The bulk alloys exhibit a Cu-induced dual-phase FCC structure, accompanied by a progressive transition from strength-dominated behavior to enhanced ductility and wear resistance with increasing Cu content. Among the investigated compositions, the alloy containing ∼30 at.% Cu achieves the optimal combination of yield strength (282.86 MPa), tensile strength (423.58 MPa), and ductility (25.2%), while higher Cu contents significantly reduce wear rates by promoting oxidative wear mechanisms and self-lubrication effects. Molecular dynamics simulations further confirm that increased Cu content lowers friction coefficients and wear volumes through oxide-layer formation and modified dislocation activity. This study demonstrates that high-throughput composition screening, combined with targeted bulk validation, provides an effective pathway for optimizing the trade-off between mechanical properties and electrical resistivity in Cu-containing high-entropy alloys, while elucidating the underlying composition-controlled mechanisms.