Hierarchical Strengthening Design in AlCrCuFeNi_2.5/CuCrZr Composites Enables Strength–Ductility–Conductivity Synergy

Developing Cu-based composites that simultaneously achieve ultra-high strength, ductility, and electrical conductivity remains critical for advanced electrical contact applications. In this work, multiphase AlCrCuFeNi_2.5 high-entropy alloy (HEA) reinforcements are incorporated into CuCrZr matrix via spark plasma sintering (SPS) and annealing, constructing hierarchically strengthened composites with optimized strength (1149 MPa)-ductility (27.6%)-conductivity (39.6% IACS) synergy. Annealing-induced precipitation of Cr-rich phases compensates for conductivity loss from interfacial diffusion while enhancing strength. During deformation, the multiphase HEA continuously activates stacking fault networks and Lomer–Cottrell locks, enabling compatible deformation with the matrix and remarkable plasticity. The strategy to introduce the novel hierarchical structure paves a new way to develop high-performance Cu-based composites.