Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 20: Topical session (Symposium MM): Hydrogen in Materials

MM 20.4: Talk

Tuesday, March 13, 2018, 11:45–12:00, H 0107

Strain Response of Nanoporous Palladium upon Hydrogenation: Contributions of Hydride Phases, Stresses and Strain Rate — •Markus Gössler, Eva-Maria Steyskal, and Roland Würschum — Inst. of Mater. Phys., TU Graz, Austria

Nanoporous (np) palladium is an interesting candidate to study hydrogen and hydride phases in nanoporous systems [1]. The high surface stresses in nanoscaled structures can affect hydrogen interactions substantially, including the formation of metal hydrides. A novel method to achieve particularly fine porosities is electrochemical dealloying, a selective dissolution process from an alloy. In this work the strain response of dealloyed np Pd samples upon electrochemical hydrogenation was studied, using an in-situ dilatometric technique [2]. Unexpected yielding of np Pd during hydrogen desorption could be associated with an enhancement of plasticity, based on the activation of an additional pathway for plastic deformation. There are indications that hydrogen solutes interact with dislocations upon hydrogen desorption at high strain rates which are discussed by analogy with the well-known mechanism of dynamic strain aging. The impact of the np-structure related surface stress on the behaviour of the strain curve will be elucidated. Acknowledgement: This work is financially supported by the Austrian Science Fund (FWF): P30070-N36.

[1] M. Hakamada et al., J.Phys.Chem.C 114 (2010) 868. [2] E.-M. Steyskal et al., Beilst.J.Nanotech. 7 (2016) 1197.