EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

In the present study, we employ a QM/MM approach, which couples DFT and MD to overcome limits inherent to both of the methods. The coupled algorithm is used to study interfaces at an atomistic level. While MM is applied to (chemically and structurally simpler) matrix regions, QM is used to treat chemical impurities and extended defects such as interfaces.

After introducing the methodology, the results of its application to interfaces in TiAl alloys will be presented. In this material system, $\alpha_2/\gamma$ phase boundaries and $\gamma/\gamma$ interfaces play a vital role in the design of novel light-weight metallic alloys. We will present detailed predictions of segregation phenomena to phase boundaries corroborated by APT data available in the literature. Finally, having a reasonable description gain boundary chemistry, we will discuss the influence of solutes on the interfacial mechanical properties.