Effect of grain size on the strain rate sensitivity of CoCrFeNi high-entropy alloy

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:782

Article

Zhao, Yakai^1,2  Wang, Xutao¹  Cao, Tangqing¹  Han, Jae-Kyung³  Kawasaki, Megumi³  Jang, Jae-il⁴  Han, Heung Nam⁵  Ramamurty, Upadrasta²  Wang, Lu¹  Xue, Yunfei¹ 

[1] Beijing Inst Technol, Sch Mat Sci & Engn, Beijing 100081, Peoples R China

[2] Nanyang Technol Univ, Sch Mech & Aerosp Engn, Singapore 639798, Singapore

[3] Oregon State Univ, Sch Mech Ind & Mfg Engn, Corvallis, OR 97331 USA

[4] Hanyang Univ, Div Mat Sci & Engn, Seoul 04763, South Korea

[5] Seoul Natl Univ, Dept Mat Sci & Engn, Seoul 08826, South Korea

关键词: High-entropy alloy;    Grain size effect;    High-pressure torsion;    Nanoindentation;    Strain-rate sensitivity;   

DOI  :  10.1016/j.msea.2020.139281

来源: Elsevier

【 摘 要 】

Strain rate sensitivity (SRS) of a face-centered cubic (fcc) CoCrFeNi high-entropy alloy (HEA) with grain sizes ranging from 57 mu m to 45 nm was investigated using nanoindentation, and was compared with those reported for conventional fcc metals. Experimental results show pronounced grain boundary strengthening in the HEA. Estimated values of the SRS parameter, m and activation volume, V*, indicate similar plastic deformation mechanisms in HEA and Ni in nanocrystalline regime that are grain boundary mediated. In coarse-grained regime, the high lattice friction stress in the HEA results in much higher m and smaller V* as compared to coarse grained Ni.

【 授权许可】

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