Preparation and properties of Ti2AlC/TiAl composites

Ti2AlC/TiAl composites were successfully synthesized using Ti powder, Al powder, TiC powder and carbon nanotubes as raw materials. After ball milling and cold pressing, the compacts were sintered in vacuum furnace at 1250. Then the density, hardness, flexural strength and fracture toughness of Ti2AlC/TiAl composites were tested. The phase composition, microstructure and crack propagation mode were analyzed by XRD, SEM and EDS. The results show that the composite is mainly composed of Ti2AlC, TiAl and a small amount of Ti3Al. A compact structure and bulk distribution of reinforcement can be obtained. When the content of Ti2AlC reaches to 30wt%, the comprehensive performance of Ti2AlC/TiAl composite is the best, and the density, hardness, flexural strength and fracture toughness are 3.80 g/cm3, 3.92 GPa, 408.42 MPa and 5.41 MPa·m1/2, respectively. By observing the fracture and crack propagation mode, it appears bridging, crack deflection, lamellar tearing and pulling out of reinforcement. It is helpful to improve the toughness of the material, but too much Ti2AlC is not conducive to improve the performance of TiAl. © 2015, Chinese Ceramic Society. All right reserved.