SKM 2023 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 32: Topical Session: Defect Phases I

MM 32.1: Topical Talk

Wednesday, March 29, 2023, 15:45–16:15, SCH A 216

Defect phase diagrams: Concepts, computational approaches and applications — Marvin Poul, Prince Mathews, Ali Tehranchi, Jing Yang, Mira Todorova, Tilmann Hickel, and •Jörg Neugebauer — Max-Planck-Insitut für Eisenforschung GmbH, Düsseldorf, Germany

Extending the well-known concept of bulk phase diagrams to defects allows to predict the thermodynamically stable defect states at any given temperature and bulk composition. Similar to bulk phase diagrams such diagrams allow to identify processing conditions where defect states with particularly desirable stoichiometries, structures and properties form. These diagrams thus provide an exciting new approach in designing materials. Modern atomistic tools based on density functional theory or machine learning potentials can provide all the necessary information to construct such phase diagrams but face severe conceptual and computational challenges: The description of such defects requires thermodynamically open boundary conditions as well as the inclusion of a large number of structural, chemical and electronic degrees of freedom. In the presentation, key concepts of efficiently sampling the large configuration spaces associated with computing defect states and phase diagrams will be discussed. Examples of how this insight can be used to understand and control grain boundary formation, morphology or improved corrosion resistance will be given.