Enhanced resistance to hydrogen embrittlement in a CrCoNi-based medium-entropy alloy via grain-boundary decoration of boron

Materials Research Letters

J. Y. He¹  T. Yang²  W. H. Liu³  X. Q. Zhuang³  J. W. Mo³  X. H. Chen³  X. Y. Zhou⁴ 

[1] Central South University;City University of Hong Kong;Harbin Institute of Technology (Shenzhen);Max-Planck-Institut für Eisenforschung GmbH;

关键词: medium entropy alloy;    hydrogen embrittlement;    grain boundary segregation;   

DOI  :  10.1080/21663831.2022.2033865

来源: DOAJ

【 摘 要 】

We found boron doping can substantially reduce the ductility-loss in the CrCoNi medium-entropy alloy after gas-hydrogen charging, from ∼71% to ∼46%, while the fracture mode transfers from predominantly intergranular to ductile transgranular dominated. The two alloys have no difference in phase-structures (single face-center-cubic), grain sizes, and grain-boundary (GB) characters. However, atom probe tomography identified apparent GB decoration of boron up to 1.5 at.% and nanometer-scaled scattered borides in boron-doped CrCoNi. Such local chemical difference leads to enhanced GB cohesion and reduced hydrogen diffusivity along GBs, resulting in improved immunity against hydrogen-embrittlement and suppressed mechanical degradation in the boron-doped CrCoNi alloy.

【 授权许可】

Unknown