Polysynthetically-twinned TiAl, which contained a high density of parallel atomically-flat interfaces within a set of identical crystallographic orientations, was explored as a potential model system for the detailed investigation of interface diffusion. Macroscopic polysynthetically-twinned crystals were grown in an optical float-zone furnace. Thin films were cut from oriented crystals, and were polished with their <110> or <112> directions normal to the film. After sputter-cleaning, Ag was deposited onto one side of the TiAl thin films. Auger spectra were obtained from these films for a wide range of sputtering and annealing conditions. The Al and Ti concentrations were analyzed, as well as those of the important impurity elements: S, Ar, C, N and O. The occurrence of Ag diffusion on the interfaces was confirmed.

Auger Spectroscopy of TiAl Interface Diffusion Specimens. D.E.Luzzi, D.Imamura, H.Inui, E.P.George, L.Heatherly, H.Yasuda, H.Mori, M.Yamaguchi: Materials Science Forum, 1999, 294-296, 389-92