A high-resolution transmission electron microscopic investigation was made of Σ = 7 {213} tilt boundaries in the pure metal, and in samples which contained 10ppmGa. Image simulation showed that a bright contrast in the transmission electron microscopic images indicated the positions of atomic columns. By measuring contrast profiles, it was found that those atoms in Al-10ppmGa which were closest to the grain boundary were anomalously shifted along the <121> direction; as compared to the equivalent atomic positions in pure Al. It was proposed that this anomalous shift was probably the reason for the higher mobility of grain boundaries in the Al-10ppmGa samples.

HRTEM Study of Σ7 Grain Boundary in Aluminium Bicrystals with and without Ga Doping. W.Hu, D.A.Molodov, B.Schönfelder, L.S.Shvindlerman, G.Gottstein: Interface Science, 2000, 8[4], 335-49