In situ high-energy X-ray diffraction study and quantitative phase analysis in the α + γ phase field of titanium aluminides

Quantitative atomic structure and phase analysis in the titanium aluminide intermetallic system of composition Ti–45Al–7.5Nb–0.5C (at.%) was conducted in situ by use of high-energy X-ray diffraction from a synchrotron and evaluated using the Rietveld method, implementing a model for atomic order in the α-phase which describes the order to disorder transition α2 → α at the eutectoid temperature. The order parameter exhibits unexpected behavior and is entangled with the competition of different kinetic processes.