Diffusion of 59Fe in single crystalline γ-TiAl intermetallic compound was investigated by the ion-beam sputter-sectioning technique at 1123 to 1303K. The diffusion coefficients measured in the directions parallel (D33) and perpendicular (D11) to the [001] axis exhibited significant anisotropy; the diffusion of 59Fe parallel to the [001] direction was faster than that perpendicular to the [001] direction. The activation energy for diffusion of 59Fe parallel to the [001] direction was smaller than that perpendicular to that direction. The anisotropy of 59Fe diffusion was opposite to that of 44Ti self-diffusion. It was suggested that this anisotropy was related to site occupation of Fe in TiAl and the jumps of atoms through vacancy jumps.

Diffusion of 59Fe in γ-TiAl Single Crystals. N.Terashita, Y.Nose, T.Ikeda, H.Nakajima, H.Inui, M.Yamaguchi: Materials Letters, 2003, 57[22-23], 3357-60