Reinforcing and toughening of TiAl composites by doping Sm2O3

Al2O3/TiAl composites were fabricated by in-situ reaction synthesis using Ti, Al, TiO2 and Sm2O3 as starting materials. Effect of the doping Sm2O3 on the microstructures and properties of the Al2O3/TiAl composites was analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and universal properties tests. The results show that the phases of the Sm2O3-doped composites are mainly composed of γ-TiAl/α2-Ti3Al matrix and reinforcing phases of Al2O3 and SmAl. The microstructures of Al2O3/TiAl composites are significantly refined with doping Sm2O3. Doping Sm2O3 has a positive effect on improving the mechanical properties of Al2O3/TiAl composites. When the Sm content is 5% (mass fraction), the flexural strength and fracture toughness reach the maximum values of 658.9 MPa and 10.13 MPa·m1/2, respectively.