Unveiling the Mechanisms of Strength-Ductility Synergy in an Additively Manufactured Nanolamellar High-Entropy Alloy

Professor Zhou Kun

Introduction

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 Al19Co20Fe20Ni41 EHEA with a nanolamellar microstructure, chosen specifically for its increased fraction of ductile face-centred cubic phase. The EHEA processed by L-PBF exhibits high yield strength exceeding 1.3 GPa together with a 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. 

 Key Highlights

  • As-printed EHEA with outstanding strength-ductility: yield strength of 1311 MPa, ultimate tensile strength 1630 MPa, uniform elongation 20%.

  • AM-enabled hierarchical heterostructure: nanoscale FCC/BCC lamellae plus mesoscale BCC-rich/BCC-lean “brick” architecture.

Conclusion

The strategy presented in this work provides a cost-effective approach for fabricating high-value alloy components and can be readily extended to the design of other dual-phase HEAs or heterogeneous metallic structural materials that require geometrical complexity and scalable manufacturing. 

Source: https://doi.org/10.1038/s41467-025-64871-4