Hierarchical heterogeneous ordering enables wide-temperature strength-ductility synergy in additively manufactured medium-entropy alloys.
basic_science · Level V
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- Record sourced from PubMed, PMID 42031814.
- Also identified by DOI 10.1038/s41467-026-72261-7.
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Abstract
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 Co<sub>30</sub>Cr<sub>13</sub>Fe<sub>13</sub>Ni<sub>30</sub>Al<sub>6</sub>Ti<sub>7</sub>Nb<sub>1</sub> (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 L1<sub>2</sub> nanoprecipitates and rod-like L2<sub>1</sub> 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.