Wetting of the low-angle grain boundaries

It is demonstrated that the classical Read–Shockley model of the low-angle grain boundary fails to predict quantitatively the misorientation angle, at which the grain boundary wetting phase transition occurs. This is because the wetting transition at the low-angle grain boundary is associated with the low value of the solid/liquid interfacial energy. For sufficiently low interfacial energies, the dislocation cores are unstable against the substitution by the pipes of the liquid phase (wetted core dislocation). The energy of the low-angle grain boundary composed of the array of wetted core dislocations is calculated under the assumptions of the circular cores. The grain boundary wetting transition occurs at the misorientation θ≈0.19b/RF, where b and RF are the Burgers vector of dislocation and the Frank's radius, respectively. The impact of wetted core dislocations on the mechanical behavior of the material is discussed.