“Special” to “general” transition of intergranular corrosion in Σ3{1 1 1} grain boundary with gradually changed misorientation

The allowable angular deviation to show the “specialness” of coincident site lattice (CSL) grain boundaries has been demonstrated directly (not statistically as was done before) by Σ3{1 1 1} pure copper bicrystal with gradually changed misorientation fabricated by diffusion bonding. The dependence of sensitivity to intergranular corrosion on angular deviation has been examined by Livingston's dislocation etchant which is sensitive to grain boundary structures. The critical angular deviation has been manifested, under which the grain boundary exhibited complete immunity to selective dissolution, and is smaller than the well-known Brandon criterion.