Huber, LiamGrabowski, BlazejMilitzer, MatthiasNeugebauer, JörgRottler, Jörg2021-04-072021-04-0720171359-64541816733547http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-ds-114109http://elib.uni-stuttgart.de/handle/11682/11410http://dx.doi.org/10.18419/opus-11393We apply a quantum mechanical/molecular mechanical (QM/MM) multiscale approach to calculate the segregation energies of Mg and Pb to two kinds of grain boundaries in Al. The first boundary, a symmetric (310)[001] ∑5 tilt boundary, is also tractable using traditional QM calculations, and serves as a validation for the QM/MM method. The second boundary is a general, low-symmetry tilt boundary that is completely inaccessible to pure QM calculations. QM/MM results for both of these boundaries are used to evaluate the accuracy of empirical (EAM) potentials for the Al-Mg and Al-Pb alloy systems. Based on these results we develop a physical model for the segregation energy based on elastic interaction and bond breaking terms. Both MM calculations with the EAM potentials and the model work quantitatively well for describing Mg-GB interaction across a wide range of local environments. For Pb, MM performance is weaker and the model provides only qualitative insight, demonstrating the utility of a QM/MM approach.eninfo:eu-repo/semantics/openAccess530article