Correlation between the energy and structure of grain boundaries in b.c.c. metals I. Symmetrical boundaries on the (110) and (100) planes

Abstract

The zero-temperature energies and equilibrium volume expansions of point-defect-free grain boundaries (GBs) on the two densest planes of b.c.c. metals have been determined using a Finnis—Sinclair potential for Mo and Johnson's potential for α-Fe. The energies and volume expansions of the (100) boundaries are found to be about two to three times larger than those of the (110) boundaries. 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 therefore, electronic many-body effects arising from a local volume dependence of the interatomic interactions are relatively unimportant.