Unveiling microstructural origins of the balanced strength-ductility combination in eutectic high-entropy alloys at cryogenic temperatures

作者：Li, Yi; Shi, Peijian^*; Wang, Mingyang; Yang, Yinpan; Wang, Yan; Li, Yiqi; Wen, Yuebo; Ren, Weili; Min, Na; Chen, Yan; Guo, Yifeng^*; Shen, Zhe; Zheng, Tianxiang; Liang, Ningning; Lu, Wenjun; Liaw, Peter K.; Zhong, Yunbo^*; Zhu, Yuntian

来源：Materials Research Letters, 2022, 10(9): 602-610.

DOI：10.1080/21663831.2022.2078169

• Eutectic high-entropy alloys
• mechanical properties
• multi-slip scenario
• compatible co-deformation
• HDI hardening

Eutectic high-entropy alloys (EHEAs) feature attractive strength-ductility balance at both ambient and cryogenic temperatures. Nevertheless, microstructural origins underpinning these balanced mechanical properties remain elusive. Here the deformation mechanisms of a recently-reported Al19Co20Fe20Ni41 EHEA were comparatively investigated at 298 and 77 K, which revealed a high frequency and density of dislocation multi-slip scenario in the soft eutectic lamellae and the corresponding compatible co-deformation in the adjacent hard lamellae that collectively endowed strong hetero-deformation-induced (HDI) hardening and excellent forest-dislocation hardening. Therefore, better ductility and tensile strength, in comparison to the other widely-studied EHEA system, could be sustained even at liquid-nitrogen temperatures. @@@ IMPACT STATEMENT We identify a new eutectic HEA system with superior strength-ductility combination at liquid-nitrogen temperatures, and provide critical microstructural insights and mechanisms into its enhanced cryogenic properties.

• 单位
  南京理工大学; 上海大学