It was recalled that an important factor, with regard to boundary-structure versus property relationships, was the occurrence of solute/boundary interactions. These could involve bulk solute concentrations which were typically in the ppm range. Experimental studies of such interactions had clearly indicated that structural differences existed among various high-angle grain boundaries. It was known that many low- boundaries had superior properties, as compared with those of high- boundaries. The low- so-called special boundaries were generally those for which  was less than 29; with a possible angular deviation of up to 15 -5/6. Experimental evidence was presented here which demonstrated the significant effect that boundary-solute interactions had upon the structural and migrational differences between low- and general grain boundaries.

K.T.Aust, G.Palumbo: Materials Science Forum, 1996, 204-206, 33-44