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

摘要

Quantitative atomic structure and phase analysis in the titanium aluminide intermetallic system of composition Ti-45Al-7.5Nb-0.5C (at. percent) 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 a-phase which describes the order to disorder transition alpha_2 - alpha at the eutec-toid temperature. The order parameter exhibits unexpected behavior and is entangled with the competition of different kinetic processes.