Unveiling the mechanisms of strength-ductility synergy in an additively manufactured nanolamellar high-entropy alloy.

Gao, Shubo; Ji, Weiming; Zhu, Qi; Jarlöv, Asker; Bai, Xueyu; Shen, Xiaojun; Liu, Yong; Nai, Mui Ling Sharon et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

The combination of alloy design and advanced manufacturing techniques inspires solutions to critical engineering challenges, such as simultaneously achieving high strength and high ductility in structural alloys. Eutectic high-entropy alloys (EHEAs) are particularly promising for their integration of both strong and ductile phases. Here, using valence electron concentration as a criterion, we employ laser powder bed fusion (L-PBF) to fabricate Al<sub>19</sub>Co<sub>20</sub>Fe<sub>20</sub>Ni<sub>41</sub> EHEA with a nanolamellar microstructure, chosen specifically for its increased fraction of ductile face-centred cubic phase. The EHEA processed by L-PBF demonstrates a combination of high yield strength exceeding 1.3 GPa and large uniform elongation of 20%. This strength-ductility synergy arises from the coherent nanoprecipitates, nanolamellar structures, hierarchical microstructure heterogeneity, and deformation-induced nanovoids activated within the hard body-centred cubic lamellae. This study provides a pathway for designing high-performance alloys by integrating multiple deformation mechanisms, offering opportunities for advanced structural material development.