Ab initio modelling of solute segregation energies to a general grain boundary. (15th June 2017)

• Record Type: Journal Article
• Authors: Huber, Liam; Grabowski, Blazej; Militzer, Matthias; Neugebauer, Jörg; Rottler, Jörg
• Is Part Of: Acta materialia. Volume 132(2017)
• Page Start: 138
• Page End: 148
• Publication Date: 2017-06-15
• Subjects: Ab initio modelling -- Multiscale modelling -- Grain boundary -- Solute segregation; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2017.04.024
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: We 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] Σ 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. Graphical abstract: Image 1