Theoretical and experimental investigations of structures and energies of Σ = 3, [112] tilt grain boundaries in copper

Abstract

Abstract Using atomistic computer simulations, symmetric and asymmetric Σ = 3 tilt grain boundaries in Cu were investigated. Equilibrium energies and structures were calculated by static and dynamic energy minimization. A semi-empirical N-body potential served as a model of the interatomic forces in Cu. The atomistic structure of the grain boundary inclined at about 84° to the {111} twin boundary was investigated by high-resolution transmission electron microscopy (HRTEM). Plotted against the inclination angle Φ112 of the boundary plane, the calculated grain boundary energies increase monotonically up to Φ112 ≈ 73°. At larger inclination angles the data indicate an energy minimum at about 80°. The computer simulations predic that boundaries equilibrated at temperatures near T = 0K are planar for inclination angles σ112 < 73°, but consist of a three-dimensional layer of predominantly body-centred-cubic (bcc) Cu for inclination angles greater than 73°. In all three-dimensional boundaries by bcc layer ...