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MM: Fachverband Metall- und Materialphysik

MM 30: Poster Session II

MM 30.30: Poster

Dienstag, 17. März 2020, 18:15–20:00, P4

Ab Initio Molecular Dynamics Simulations of Chemical Processes at the Crack Tip — •Tobias Müller and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer-Chemistry-Center, FAU Erlangen-Nürnberg

Fracture of materials takes place in an environment, usually air or liquid water. When a crack propagates, the newly created surfaces become exposed to the molecules of the surrounding gas phase or liquid, e.g. oxygen and water, which leads to a series of chemical processes. For example, the molecules can attack a stretched bond at the crack tip, giving rise to chemically activated bond breaking and resulting in subcritical crack growth and stress corrosion cracking. In order to encompass the complex chemical interplay between bond breaking at the crack tip and the adsorption/bond saturation with molecules from the environment, unbiased and accurate quantum-chemical methods are needed. Here we show first ab initio molecular dynamics simulations for silicon to study stress corrosion cracking by subcritical loads. A series of Car-Parrinello molecular dynamics (CPMD) simulations were performed with different loads and for crack tips exposed to hydrogen, oxygen or water.