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MM: Fachverband Metall- und Materialphysik

MM 32: Topical Session: Defect Phases I

MM 32.8: Topical Talk

Mittwoch, 29. März 2023, 18:00–18:30, SCH A 216

Towards a Rigorous Theory of Grain Boundary Segregation in Polycrystals — •Christopher Schuh — MIT, Department of Materials Science and Engineering, Cambridge, MA USA

Although grain boundary segregation is pervasive across metals and materials, the models used to describe it generally fall short in one of two ways. One class of models is too approximate, using, e.g., a scalar 'average' segregation energy; the other is too detailed, focusing on specific atomic sites in select boundaries. Both approaches fail to capture the complex range of sites in the grain boundary network of polycrystals. This talk will overview a project in our group at MIT that aims to develop a new type of grain boundary segregation theory that bridges this gap: it is designed to be quantitatively accurate at the level of specific grain boundary sites, but simple enough to admit solution with an isotherm that can be analytically represented. The approach is based on the parameterization of segregation spectra: distribution functions of all the key thermodynamic quantities necessary to capture the full physics of segregation in polycrystals. We address the spectra of: segregation sites and their enthalpies, interaction parameters amongst solutes, and vibrational contributions to the segregation free energy. After describing computational methods to determine these spectra, we then address the problem of high-throughput computation of them for many alloy systems using tools of data science.