Hierarchical heterogeneous ordering enables wide-temperature strength-ductility synergy in additively manufactured medium-entropy alloys

Maintaining a stable balance between strength and ductility across a wide temperature range remains a critical challenge for structural metallic materials. Here, a compositionally tailored Co30Cr13Fe13Ni30Al6Ti7Nb1 (at.%) alloy is fabricated by additive manufacturing and subjected to tailored thermal treatments to develop a hierarchical heterogeneous ordered microstructure. The resulting architecture integrates multiscale grain and cellular frameworks with ordered L12 nanoprecipitates and rod-like L21 phases, enabling concurrent strengthening and sustained plasticity. Mechanical testing from 77 to 873 K demonstrates yield and ultimate tensile strengths of approximately 0.9-1.2 GPa and 1.2-1.7 GPa, respectively, together with uniform elongations of 16-24%. This wide-temperature strength-ductility synergy is associated with distinct deformation responses operating across temperatures, enabled by the hierarchical architecture, which sustains strain hardening across multiple length scales. These results highlight hierarchical ordering as an effective microstructural strategy for maintaining a stable strength-ductility balance over a broad temperature range. An additively manufactured medium entropy alloy with hierarchical ordering maintains high strength and ductility from 77 to 873 K, offering a pathway to structural materials capable of reliable performance across wide temperature ranges.