Hierarchical crack buffering triples ductility in eutectic herringbone high-entropy alloys

• DOI: 10.1126/science.abf6986
• Publication Date: 2021-08-19T19:16:16Z
• Authors: Peijian Shi; Runguang Li; Yi Li; Yuebo Wen; Yunbo Zhong; Weili Ren; Zhe Shen; Tianxiang Zheng; Jianchao Peng; Xue Liang; Pengfei Hu; Na Min; Yong Zhang; Yang Ren; Peter K. Liaw; Dierk Raabe; Yan-Dong Wang
• Keywords: Elongation; Ductility (Earth science); Structural material

In human-made malleable materials, microdamage such as cracking usually limits material lifetime. Some biological composites, bone, have hierarchical microstructures that tolerate cracks but cannot withstand high elongation. We demonstrate a directionally solidified eutectic high-entropy alloy (EHEA) successfully reconciles crack tolerance and The has hierarchically organized herringbone structure enables bionic-inspired buffering. This effect guides stable, persistent crystallographic nucleation growth of multiple microcracks in abundant poor-deformability microstructures. Hierarchical buffering by adjacent dynamic strain-hardened features helps the to avoid catastrophic percolation. Our self-buffering yields an ultrahigh uniform tensile elongation (~50%), three times conventional nonbuffering EHEAs, without sacrificing strength.