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We have analyzed the phase relationships in two titanium aluminides containing 3.4 at. % Mo with different aluminum compositions. The alloys were first homogenized in the /3 field, then cooled continuously at different cooling rates from 80 °C/s to 0.1 °C/s. The continuous cooling transformation diagrams (CCT) show that phase transformations and resulting microstructures are highly dependent on cooling rate. The microstructure consists of ordered a 2 (DOi 9 ), ordered y3 0 (B2), and athermal a (hexagonal) phases. The "tweed microstructure" is observed. The evolution of microhardness was determined as well as the relative partitioning of Al and Mo in (a 2 ', a 2 ) and /3 0 phases as a function of cooling rate.