High impact toughness of CrCoNi medium-entropy alloy at liquid-helium temperature

SCRIPTA MATERIALIA

卷:172

Article

Yang, Muxin¹  Zhou, Lingling¹  Wang, Chang²  Jiang, Ping¹  Yuan, Fuping^1,4  Ma, Evan³  Wu, Xiaolei^1,4 

[1] Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China

[2] Cent Iron & Steel Res Inst, Cent Lab, Beijing 100081, Peoples R China

[3] Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA

[4] Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China

关键词: Impact fracture toughness;    Twinning;    Ductility;    High-entropy alloy;    Strain hardening;   

DOI  :  10.1016/j.scriptamat.2019.07.010

来源: Elsevier

【 摘 要 】

We show that face-centered-cubic CrCoNi medium-entropy alloy sustains a Charpy V-notch impact toughness (A(K)) as high as 340 J at 4 K. Deformation twinning (DT) is rendered exceptionally profuse by this alloy's low stacking fault energy, combined with liquid-helium temperature and high strain rates that both incur high stresses to favor DT across a large plastic zone. This efficiently dissipates imposed mechanical energy, accumulates defects to sustain high strain hardening, and restrains strain localization events from evolving into major shear bands. Martensitic transformation to hexagonal phase is insignificant. CrCoNi is therefore a strong competitor to the best existing cryogenic alloys. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

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