The behavior of grain boundary sliding in pure and Y-doped Al2O3 was measured directly at high temperatures by using bicrystal experiments. Bicrystals were fabricated which contained a random grain boundary, with or without Y ions. High-resolution transmission electron microscopic observations and energy-dispersive X-ray spectroscopic analyses showed that bicrystals were successfully joined at the atomic scale, and doped Y ions segregated along the grain boundaries. It was found, by compressive creep testing, that the grain-boundary sliding rate was restrained by 2 orders of magnitude, due to Y additions, as compared to that in undoped bicrystals.

Direct Measurements of Grain Boundary Sliding in Yttrium-Doped Alumina Bicrystals. K.Matsunaga, H.Nishimura, H.Muto, T.Yamamoto, Y.Ikuhara: Applied Physics Letters, 2003, 82[8], 1179-81