STRUCTURE-ENERGY CORRELATION FOR GRAIN-BOUNDARIES IN FCC METALS .2. BOUNDARIES ON THE (110) AND (113) PLANES

The zero-temperature energies and equilibrium volume expansions of point-defect free grain boundaries (GBs) on the third and fourth 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 (110) and (113) boundaries are typically about 50% larger than for the (100) boundaries and about three to four times those of the (111) boundaries investigated earlier. This correlation between planar density, i.e., interplanar spacing, and GB energy as well as volume expansion is shown to be closely related to the structural disorder in the interface region. A practically linear relationship between GB energy and volume expansion is observed. Based on the special geometry and properties of the symmetrical tilt configuration on a given lattice plane (which is obtained for a twist angle of 180°), it is proposed to consider these planar defects as generalized (i.e., inverted) stacking faults rather than high-angle grain boundaries.