Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 31: Mechanical properties II - Characterisation mechanics
MM 31.5: Vortrag
Dienstag, 1. April 2014, 16:45–17:00, IFW D
The influence of dissolved hydrogen in palladium on the pop-in load — •Martin Deutges1, Christine Borchers1, and Reiner Kirchheim1,2 — 1Institut für Materialphysik, Georg-August Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, Japan
The transition of elastic to plastic deformation in an initial defect free material is accompanied by the creation of a new dislocation loop. Nanoindentation allows to observe this event and the load at which this happens is called pop-in load.
It is well known that hydrogen affects defect formation. As an example, dissolved hydrogen in palladium facilitates the formation of dislocations, leading to an increase in dislocation density [1].
The palladium-hydrogen system was chosen to analyze this effect with nanoindention. For this purpose an in-situ setup is used to keep a defined hydrogen concentration within the α-phase of the palladium-hydrogen system.
These experiments can be analyzed using the defactants concept [2], the basis of which is the assumption that a decrease of the overall free energy by the segregation of solute atoms to a defect can be ascribed to a decrease of the defect formation energy.
[1] Y.Z. Chen et al., Scripta Mater. 68 (2013) 743.
[2] R. Kirchheim, Acta Mater. 55 (2007) 5129.