Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session

MM 20.36: Poster

Tuesday, March 27, 2007, 14:45–18:00, Poster C

Hydrogen in epitaxial V-8at%Fe films on Al2O3 substrate — •Ryota Gemma, Talaat Al-Kassab, Reiner Kirchheim, and Astrid Pudnt — Institut fuer Materialphysik, Goettingen, Germany

In this study, P-C-T properties and hydrogen-induced stresses of V-8at%Fe 100nm thick films with different microstructures and different initial strain conditions were investigated by measuring electromotive force (EMF) and in-plane stress simultaneously. The phase boundaries for the solid solution cH,α and the hydride cH,β were determined. The local chemistry of the hydride (deuteride) was investigated by performing tomographic atom probe analysis (TAP). The phase boundaries were found to be microstructure dependent: The α-phase solubility limit cH,α=0.1 H/V and cH,β= 0.45 H/V for films with small domain size, and cH, α=0.1 H/V and cH,β= 0.6 H/V for films with large domain size. The total in-plane compressive stress was smaller in small-domain samples compared to larger-domain samples. It was shown that the measured slope of P-C isotherm depends on initial stress condition and the microstructure. TAP analysis at 22K detected a plate-like deuteride VD0.65 at Pd/V interface. The concentration of this precipitate was in accordance with the expectations.