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MM: Fachverband Metall- und Materialphysik

MM 11: Topical Session: Defects of Defects

MM 11.2: Vortrag

Dienstag, 18. März 2025, 10:45–11:00, H10

Atomistic simulation of point defects behavior inside grain boundaries — •Sergei Starikov, Matous Mrovec, and Ralf Drautz — Ruhr University Bochum, ICAMS, 44801 Bochum, Germany

The properties of point defects play a key role in the description of many phenomena within grain boundaries (GBs), such as pre-melting or atomic diffusion. Compared to the bulk, point defects inside GB are characterized by low formation energy and high complexity. Thus, the thermodynamic/kinetic properties of GBs strongly depend on the behavior of point defects. To reveal general aspects of this relationship, we studied behavior of vacancies and self-interstitial atoms inside tilt grain boundaries for several metals (Ni, Al, Fe, Nb, Mo and W) using atomistic modeling. The simulations revealed that the self-diffusion along the tilt GBs at low/moderate temperatures is mostly driven by migration of self-interstitial atoms. However, heating leads to a change in the GB diffusion mechanism to a more complex exchange process, not related to specific defects, but similar to atomic diffusion in a liquid. This change is due to the disordering complexion transition of GBs, which also significantly affects GB mobility.

Keywords: point defects; atomistic simulation