THERMODYNAMIC CALCULATION OF DIFFUSION PATHS APPLIED TO THE OXIDATIONOF GAMMA-TIAL

The thermal oxidation process of gamma-TiAl is discussed regarding kin etic and thermodynamic aspects. A simple thermodynamic model allows th e calculation of diffusion paths and leads to a better comprehension o f the role of thermodynamic and kinetic factors in diffusion processes . The calculations allow a reproduction of the experimental results. M oreover, it is possible to predict results in regions not yet experime ntally determined. The advantage of potential phase diagrams compared with concentration phase diagrams is discussed for diffusion processes using the Ti-Al-O system as example.