Hydrogen effect on dislocation nucleation in a ferritic alloy Fe-15Cr as observed per nanoindentation

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

卷:604

Article

Gaspard, V.¹  Kermouche, G.¹  Delafosse, D.¹  Barnoush, A.² 

[1] Ecole Natl Super Mines, CNRS, LGF, UMR5307, F-42023 St Etienne, France

[2] Norwegian Univ Sci & Technol, Dept Engn Design & Mat, N-7034 Trondheim, Norway

关键词: Hydrogen;    Nanoindentation;    Crystal anisotropy;    Dislocation nucleation;   

DOI  :  10.1016/j.msea.2014.02.041

来源: Elsevier

【 摘 要 】

Hydrogen effects on dislocation nucleation in polycrystalline ferritic Fe-15Cr binary alloy were investigated using in situ electrochemical nanoindentation. Linear elastic finite element calculations taking account of the cubic symmetry of BCC crystals were made to extract the resolved shear stresses on the different slip systems of the indented grains. It is shown that the resolved shear stresses corresponding to the experimentally measured pop-in loads are compatible with homogeneous dislocation nucleation. The resolved shear stress necessary to nucleate dislocations from defect-free crystals was estimated at mu/12-mu/13 without hydrogen. Cathodically charged hydrogen reduces the shear strength of the crystal by 8.5%-19.8%, thus promoting dislocation multiplication. (C) 2014 Elsevier B.V. All rights reserved.

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