The misorientation dependence of the energy of grain boundaries in hexagonal close-packed metals was predicted by using the disclination structural unit model, and continuum solutions, for interfacial disclination dipoles in elastically anisotropic and inhomogeneous bicrystals. For [1¯1▪0] symmetrical tilt boundaries in these metals, it was shown that the dipole stress field and the grain-boundary energy depended strongly upon the misorientation. In particular, the dipole stress field was more localized in high-angle boundaries than in low-angle boundaries. Severe distortion of the stress field resulted from even a small inhomogeneity, and homogeneous isotropic solutions failed to reproduce the dependence of the stress field upon misorientation. The energy versus misorientation curve was characterized by cusps that were associated with favored boundaries, by local energy maxima between the cusps, and by regions of high and low average energies; demarcated by favored (11▪2) boundaries. The maximum energy occurred near to the misorientation of 23°; which corresponded to the (11▪16) plane. The grain-boundary energy of Co was about twice that of Ti, for most misorientations.

Misorientation Dependence of the Energy of Symmetrical Tilt Boundaries in HCP Metals - Prediction by the Disclination-Structural Unit Model. M.S.Wu, A.A.Nazarov, K.Zhou: Philosophical Magazine, 2004, 84[8], 785-806