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 α₂(Ti₃Al)+γ(TiAl) phases with lamellar structure and γ(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°C for 4 h, and the Ti₂AlC short fibers are enlarged and secondary Ti₂AlC is precipitated after the annealing treatment.