Structure-energy correlation for grain boundaries in F.C.C. metals

The zero-temperature energies and equilibrium volume expansions of point-defect free grain boundaries (GBs) on the two densest planes of f.c.c. Cu have been determined using an embedded atom method (EAM) and a Lennard--Jones (LJ) potential. It is found that the energies and volume expansions of the (100) boundaries are about 2--3 times larger than those of the (111) boundaries. This correlation between the GB energy and the densest planes is analyzed in terms of the structural disorder in the interface region. A close correlation between large volume expansion and high GB energy is observed. Since both potentials yield qualitatively very similar results it is concluded that the short-range repulsion between atoms is the dominating contribution to the energy in the GB region and that therefore, electronic effects arising from a local volume dependence of the interatomic interactions are relatively unimportant