Computer simulation of grain boundaries was carried out for alloys with L12 and B2 superlattice structures. This covered symmetrical tilt grain boundaries, Σ = 5 [100](012) and Σ = 5 [100](013), with an [001] turning axis and misorientation angles of 53.1 and 36.9º. The atomic interactions were described by empirical Morse central-force potentials. The atomic structures and energies of the grain boundaries were investigated by constructing the γ-surface by using 3 relaxation techniques. One was rigid 2-dimensional relaxation in which the atoms of each grain remained in their sites on the corresponding lattices. The others were rigid 3-dimensional relaxation and full atomic relaxation. It was shown that Σ = 5 tilt grain boundaries in both compounds had several steady states. The present results were compared with a coincidence site lattice geometrical model. The grain boundaries in this model were unstable, but stabilization could be achieved by imposing an additional displacement along some vector in the plane of the defect.

Computer Simulation of Tilt Grain Boundaries in Alloys with L12 and B2 Superlattices. Starostenkov, M.D., Demyanov, B.F., Sverdlova, E.L., Kustov, S.L., Grakhov, E.L.: Materials Science Forum, 1999, 294-296, 215-8