Triple junction and grain boundary diffusion in the Ni/Cu system

Atomic transport along triple junctions (TJs) and grain boundaries (GBs) has been measured by atom probe tomography in nanocrystalline Ni/Cu bilayers. Heat treatment was chosen in the kinetic C-B regime according to generalized Harrison categories for the hierarchy of volume, GB and TJ transport. Diffusion coefficients at 623 K were found to be 4.65 × 10 −20 and 1.65 × 10 −17 m 2 s −1 for the GB and TJ, respectively. Thus, TJs represent a significantly faster diffusion route than GBs.