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Enhanced strength–ductility synergy in ultrafine-grained eutectic high-entropy alloys by inheriting microstructural lamellae

2019; Nature Portfolio; Volume: 10; Issue: 1 Linguagem: Inglês

10.1038/s41467-019-08460-2

2041-1723

Peijian Shi, Weili Ren, Tianxiang Zheng, Zhongming Ren, Xueling Hou, Jianchao Peng, Pengfei Hu, Yanfei Gao, Yunbo Zhong, Peter K. Liaw,

Advanced materials and composites

Abstract Realizing improved strength–ductility synergy in eutectic alloys acting as in situ composite materials remains a challenge in conventional eutectic systems, which is why eutectic high-entropy alloys (EHEAs), a newly-emerging multi-principal-element eutectic category, may offer wider in situ composite possibilities. Here, we use an AlCoCrFeNi 2.1 EHEA to engineer an ultrafine-grained duplex microstructure that deliberately inherits its composite lamellar nature by tailored thermo-mechanical processing to achieve property combinations which are not accessible to previously-reported reinforcement methodologies. The as-prepared samples exhibit hierarchically-structural heterogeneity due to phase decomposition, and the improved mechanical response during deformation is attributed to both a two-hierarchical constraint effect and a self-generated microcrack-arresting mechanism. This work provides a pathway for strengthening eutectic alloys and widens the design toolbox for high-performance materials based upon EHEAs.