Interphase boundary diffusion of Ti-44 in two-phase TiAl with lamellar alpha(2)/gamma structure

Ti-44 self-diffusion in alpha(2)/gamma interphase boundaries in two-phase polysynthetically twinned (PST) TiAl was measured for the first time. The diffusivity turns out to be in line with the grain-boundary (GB) self-diffusivity in Al-rich alpha(2)-Ti3Al. This phenomenon correlates with the specific atomistic structure of the alpha(2)/gamma interfaces in two-phase PST-TiAl. The contribution of Ti GB diffusion along gamma/gamma twin interfaces was not possible to reliably detect on the present penetration profiles that means that this diffusion mode is much slower than Ti self-diffusion along the alpha(2)/gamma interphase boundaries. (CSA)