Regensburg 2022 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 6: Computational Materials Modelling: Defects / Alloys

MM 6.3: Talk

Monday, September 5, 2022, 16:15–16:30, H44

Analytic description of grain boundary segregation, tension, and formation energy in the copper–nickel system — Tamara Krauß, Felix Fischer, and •Sebastian Eich — Institut für Materialwissenschaft — Lehrstuhl für Materialphysik, Universität Stuttgart

In this atomistic study, a recently proposed segregation model [1] is applied to segregation data of an exemplary Σ 5 grain boundary (GB), which is investigated using a copper–nickel embedded-atom method potential. Segregation in the semi-grandcanonical ensemble is systematically studied by varying the chemical potential in order to explore the full composition range for temperatures from 500 K to 1000 K. As a major thermodynamic feature, the mentioned segregation model avoids the usage of interface compositions, for which an arbitrary volume must be defined, but rather models the thermodynamically unambiguous solute excess. It was shown that the solute excess and the interface formation energy could be described very accurately over a wide range of temperatures and over the entire composition. Since the model was initially derived for systems without lattice mismatch, the copper–nickel system with a mismatch of roughly 2.7% is chosen in this study to further extend the segregation model by a linear-elastic theory to also account for the interface tensions. Using this extended model, it will be shown that the solute excess, GB tensions, and GB formation energies can be derived from an effective energy of segregation for all temperatures and over the whole composition range [2].
[1] T. Krauß, S. M. Eich, Acta Mater. 187, 73 (2020)
[2] F. Fischer, S. M. Eich, Acta Mater. 201, 364 (2020)