Cryogenic mechanical behaviors of CrMnFeCoNi high-entropy alloy

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

卷:789

Article

Fu, Wujing^1,2  Zheng, Wei³  Huang, Yongjiang^1,2  Guo, Fangmin⁴  Jiang, Songshan^1,2  Xue, Peng^1,2  Ren, Yang⁵  Fan, Hongbo^1,2  Ning, Zhiliang²  Sun, Jianfei² 

[1] Harbin Inst Technol, State Key Lab Adv Welding & Joining, Harbin 150001, Peoples R China

[2] Harbin Inst Technol, Sch Mat Sci & Engn, Harbin 150001, Peoples R China

[3] Xian Space Engine Co Ltd, Xian 710021, Peoples R China

[4] China Univ Petr, Coll New Energy & Mat, Beijing 102249, Peoples R China

[5] Argonne Natl Lab, Xray Sci Div, 9700 S Cass Ave, Argonne, IL 60439 USA

关键词: High-entropy alloy;    High energy X-ray diffraction;    Stacking faults;    Nano-twins;    Cryogenic temperature;   

DOI  :  10.1016/j.msea.2020.139579

来源: Elsevier

【 摘 要 】

The CrMnFeCoNi high-entropy alloy (HEA) exhibits higher yield strength, ultimate strength and ductility at lower temperature. To further clarify the effect of the testing temperature on microstructure evolution, in-situ synchrotron-based high-energy X-ray diffraction tensile tests were carried out from 298 K down to 123 K. The enhanced yield strength of the alloy at cryogenic temperatures can be attributed to the greater lattice distortion prior to plastic deformation. Higher strain hardening rate leads to the simultaneously enhanced strength and ductility of the studied HEA below room temperature. Both dynamic Hall-Petch hardening (twinning) and dislocation hardening provide high work hardening capacity for this alloy during the plastic deformation at cryogenic temperatures. The increased dislocation density and nano-twins at cryogenic temperatures can be attributed to the decrease in the stacking fault energy as the deformation temperature decreases. These studies could provide an in-depth understanding for the strengthening mechanisms of the HEA in different temperature conditions and guide the exploration of HEAs with superb mechanical properties at cryogenic environments.

【 授权许可】

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