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MM: Fachverband Metall- und Materialphysik

MM 31: Postersitzung II

MM 31.49: Poster

Mittwoch, 16. März 2011, 17:15–18:45, P5

Effect of hydrogen on the multiplication of dislocations in cold-rolled palladium — •Hans Peter Barth, Yuzeng Chen, and Reiner Kirchheim — Institut für Materialphysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Deutschland

According to a novel defectant (defect acting agents) concept (R. Kirchheim, IJMR (Z. Metallkde) 100 (2009) 483 and Acta Materialia 55 (2007) 5129 and 5139), the solute-defect interaction in materials can reduce defect formation energies. In the present work, the influence of hydrogen (defactant) on the multiplication of dislocations in cold-rolled palladium is studied. Palladium is used as a model system because it offers a sufficient hydrogen solubility and fast hydrogen diffusion. Well annealed palladium was electrochemically charged with different amounts of hydrogen (≤1at%) and subsequently cold-rolled to a certain deformation degree. Pure palladium was also cold-rolled to the same deformation degree for comparison. Afterwards, the hydrogen was electrochemically uncharged from the deformed samples. Dislocation densities were studied by means of XRD and electromotive force (EMF) measurements during hydrogen recharging. Compared to pure palladium, X-ray profiles of samples charged with hydrogen prior to deformation exhibit more significant Bragg peak broadening, indicating higher dislocation densities. EMF measurements confirm the conclusion from the XRD measurements. Both methods suggest hydrogen can facilitate the multiplication of dislocations in palladium. Apart from the above results, a new experimental setup for in-situ EMF measurements during tensile tests will be shown.