A computational procedure was proposed for creating a stable equilibrium triple-junction with controlled grain misorientations. This procedure was applied to construct a triple-junction between a Σ5 (210) grain boundary and two general high-angle grain boundaries in copper and calculate the diffusion coefficients along the triple-junction and the grain boundaries using molecular dynamics with an embedded-atom potential. The triple-junction diffusion was only a factor of 2 faster than diffusion in the Σ5 grain boundary but significantly faster than diffusion in the general grain boundaries. Both the grain boundaries and the triple-junction studied here exhibited a pre-melting behavior near to the bulk melting point, where their diffusivities converge to the diffusivity of bulk liquid. Although the results were consistent with the common assumption that triple-junction diffusion was generally faster than grain boundary diffusion, the difference between the two diffusivities did not appear to be large enough to ensure a significant contribution of triple-junctions to diffusional creep in polycrystals at high temperatures.

Molecular Dynamics Modelling of Self-Diffusion Along a Triple Junction. Frolov, T., Mishin, Y.: Physical Review B, 2009, 79[17], 174110