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MM: Fachverband Metall- und Materialphysik
MM 31: Topical Session: Hydrogen in Materials: from Storage to Embrittlement V
MM 31.2: Vortrag
Mittwoch, 20. März 2024, 10:45–11:00, C 130
Revealing hydrogen-rich phases in NiTi shape memory alloys — •David Holec1, Anna M. Paulik1, Adam Weiser2, Juraj Todt1, Jitka Holcova1, Jozef Keckes1, and Antonin Dlouhy2 — 1Department of Materials Science, Montanuniversität Leoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria — 2Institute of Physics of Materials ASCR, Zizkova 22, 616 62 Brno, Czech Republic
The shape memory alloy NiTi is particularly popular for medical applications and implants due to its excellent biocompatibility and corrosion resistance. Specifically, the interaction with hydrogen is critical due to its natural prevalence in living tissues.
The focus of this work is the characterization of NiTi hydrides using the density functional. Based on experimental observations, structural models have been created for different hydrogen concentrations and distributions. The formation energy has been calculated and compared between the models to find the most stable hydride structure. This is further complemented using Monte Carlo optimization of interstitial H distributions, using DFT-derived ML interatomic potential. The thus obtained compositional dependence of structural parameters is used to rationalize observed variations in the B2 and B19* lattice parameters and associated volumetric changes obtained from the in-situ X-ray synchrotron diffraction measurement during the H uptake experiment.
Keywords: NiTi; hydrides; DFT; synchrotron