Dresden 2006 – wissenschaftliches Programm

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MM: Metall- und Materialphysik

MM 14: Hydrogen in Metals I

MM 14.3: Vortrag

Dienstag, 28. März 2006, 10:45–11:00, IFW D

Mechanism of hydrogen embrittlement in nickel, studied with in situ electrochemical nanoindentation — •Afrooz Barnoush and Horst Vehoff — Saarland University, Department of Materials Science, Bldg. D22. P.O. Box 151150, D-66041 Saarbruecken, Germany

The effect of hydrogen on the nucleation and multiplication of dislocations is examined on precisely oriented Ni (111) surfaces with a specifically designed nanoindentation set up for in-situ electrochemical experiments. With this set up, for the first time hydrogen/deformation interaction has been studied in-situ on a nano-scale under realistic conditions. The effect of the electrochemical potential on the indent load displacement curve, especially the unstable elastic plastic transition is studied in detail. Not only the surface films but also the local plasticity is influenced strongly by the potential. The experiments allowed to exclude surface from hydrogen effects. Clear evidence is provided that hydrogen atoms facilitate homogenous dislocation nucleation.