Production of TiAl-Based Composites Reinforced with Al2O3 and Ti2AlC/Al2O3 by Explosion Synthesis

Combustion synthesis in the mode of explosion synthesis was used to fabricate TiAl-Al2O3 and TiAl-Ti2AlC-Al2O3 composites.Theses composites were successfully synthesized with compressed samples from elemental powder mixtures of TiO2, Al and C.The XRD analysis was conducted for in situ composites characterization. Scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was utilized to confirm results. The experimental results showed that thermite reaction of Alwith TiO2 causes to in situ TiAl-Al2O3 composite formation. By addition of carbon powder to thermite mixture, ternary carbide Ti2AlC and TiAl-Ti2AlC-Al2O3 composite was formed. With low carbon in thermite mixture, direct formation of Ti2AlC without ofintermediate TiC is reasonable. It is suggest that after TiAl formation, Ti2AlC percipitated from molten TiAl in vicinity of carbon particles. SEM micrographs show that carbon addition to thermite mixture changes the microstructure to a laminated form withplate-like grains.