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MM: Fachverband Metall- und Materialphysik

MM 9: Hydrogen in metals II: Multiscale simulations

MM 9.1: Topical Talk

Montag, 16. März 2015, 11:45–12:15, TC 006

Multiscale modeling of hydrogen-dislocation interaction — •Gerard Paul Leyson, Blazej Grabowski, and Jörg Neugebauer — Max-Planck-Straße 1, 40237 Düsseldorf, Germany

It has been well documented that hydrogen promotes embrittlement in a wide variety of materials. Despite the fact that the phenomenon is known for over a hundred years, the atomistic origin of hydrogen embrittlement is not well understood. One of the most promising models to explain hydrogen embrittlement is the Hydrogen Enhanced Local Plasticity (HELP) mechanism, which is based on the interaction between dislocations and hydrogen solutes. This mechanism has been well studied, but a quantitative connection between the hydrogen localization around dislocations and macroscopic embrittlement has yet to be achieved. To make this connection, we have developed a multi-scale model that can take into account the different length- and time-scale associated with the phenomenon, as well as takes into account the chemical interaction between hydrogen atoms. The hydrogen concentration profile generated by the model are in excellent agreement with direct atomistic simulations and predicts the correct relaxed dislocation core structure due to the formation of the nano-hydride, while being four orders of magnitudes faster. Direct connection with experiments was made by predicting the decrease in pop-in stress observed in hydrogen-charged nano-indentation experiments as a function of hydrogen chemical potential and temperature.