Hydrogen-enhanced intergranular failure of sulfur-doped nickel grain boundary: In situ electrochemical micro-cantilever bending vs. DFT

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

卷:794

Article

Hajilou, Tarlan¹  Taji, Iman¹  Christien, Frederic²  He, Shuang^3,4  Scheiber, Daniel³  Ecker, Werner³  Pippan, Reinhard⁵  Razumovskiy, Vsevolod, I³  Barnoush, Afrooz¹ 

[1] Norwegian Univ Sci & Technol, Dept Mech & Ind Engn, N-7491 Trondheim, Norway

[2] Univ Lyon, Ctr SMS, CNRS, Mines St Etienne,UMR 5307,LGF, F-42023 St Etienne, France

[3] Mat Ctr Leoben Forsch GmbH, Roseggerstr 12, A-8700 Leoben, Austria

[4] Univ Leoben, Dept Mat Sci, Jahnstr 12, A-8700 Leoben, Austria

[5] Austrian Acad Sci, Erich Schmid Inst Mat Sci, Jahnstr 12, A-8700 Leoben, Austria

关键词: Hydrogen embrittlement;    Nickel;    Sulfur segregation;    Intergranular cracking;    Density functional theory;    Micro-cantilever;   

DOI  :  10.1016/j.msea.2020.139967

来源: Elsevier

【 摘 要 】

Intergranular failure of nickel (Ni) single grain boundaries (GBs) owing to the segregation of sulfur (S), hydrogen (H), and their co-segregation has been investigated by employing micro-cantilever bending tests and density functional theory (DFT) calculations. A pure Ni GB shows completely plastic behavior with no fracture observed in the experiments. Electrochemical H-charging of the sample with no S present in the GB leads to a crack formed at the notch tip, which propagates by means of the mixed plastic-brittle fracture mode. Cantilever testing of the H-charged GB with S results in a clear brittle fracture of the GB. The co-segregation of S and H shifts the sudden drop in the load-displacement curves to smaller values of displacement. This is explained by the combined effect of these elements on the work of separation of the selected GB leading to severely decreased GB cohesion.

【 授权许可】

Free