PRODUCTION OF TiAl/Al2O3 AND TiAl/Ti2AlC/Al2O3 COMPOSITES BY EXPLOSION SYNTHESIS

Thermal explosion mode of combustion synthesis was used to fabricate TiAl-Al2O3 and TiAl-Ti2AlC-Al2O3 composites from elemental powder mixtures of TiO2, Al and C and characterized by XRD and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive Spectroscopy (EDS). The experimental results showed that thermite reaction of Al with TiO2 caused TiAl-Al2O3 composite formation. By adding carbon powder to the thermite mixture, ternary carbide Ti2AlC and TiAl-Ti2AlC-Al2O3 composite were formed. With low carbon in thermite mixture, direct formation of Ti2AlC without intermediate TiC was observed. After TiAl formation, Ti2AlC precipitated from molten TiAl in the vicinity of carbon particles. SEM micrographs show that addition of carbon to thermite mixture changes the microstructure to a laminated form with plate-like grains.