Microstructure and Reaction Process of In-situ Ti2AlC/TiAl Composite

Ti2AlC/TiAl composite was prepared with self-propagating high-temperature synthesis (SHS) followed by vacuum arc melting using Ti, Al powers and short carbon fibers as raw materials. Precipitated phases and formed microstructures of Ti2AlC/TiAl composite were investigated by means of X-ray diffraction, scanning electron microscope and transmission electron microscopy, and the reaction process was also discussed. Results show the microstructure of as-cast Ti2AlC/TiAl composite is composed of Ti2AlC, TiAl and Ti3Al phases, the matrix are mainly of alpha(2)(Ti3Al)+gamma(TiAl) phases with lamellar structure and gamma(TiAl) phase with equiaxed structure, and the precipitated in-situ Ti2AlC short fibers or particles dispersively distribute in the matrix. Ti3Al phase is decomposed to TiAl and Ti2AlC particles after annealed at 1200 degrees C for 4 h, and the Ti2AlC short fibers are enlarged and secondary Ti2AlC is precipitated after the annealing treatment.