Institute of Quantum Materials Science, IQMS

Segregation of impurity on the grain boundaries

A.R. Kuznetsov, Yu.N. Gornostyrev

International Ural Seminar "Radiation Damage Physics of Metals and Alloys"
Snezhinsk, February 2011

The segregation of solute and impurity atoms on grain boundary (GB) play important role in phase stability, physical and mechanical properties of alloys. To make clear microscopic mechanisms of the segregation formation we employ density functional theory methods PAW-VASP with taking into account atomic relaxation and calculated electronic structure and total energy of crystal of fcc Al which contain special GB and solute atom Mg or Si. We found that charge transfer give major contribution in case of symmetric GB. In the same time the deformation interaction is dominate for GB which show significant atomic relaxation lead to increase of density of atomic packing.

Fig. 1. In contrast with Mg the substitution of Al atom by Si in core of GB results in the formation of strong covalent bonding and reconstruction of GB structure. Fig. 2. Interaction energy between solute elements and grain boundary Σ5{210}[001] in Al from ab-initio calculations