Papers by Author: Shao Dan Li

Abstract: TiAl/Ti₅Si₃ in situ composites were successfully fabricated by reactive hot-press method from powder mixtures of Ti, Al and Si. The influence of the Si addition on the microstructures and mechanical properties of TiAl/Ti₅Si₃ composites was investigated in detail. The results show that an appropriate amount of addition of Si refined the matrix structure obviously due to the in situ formed Ti₅Si₃, and as a result, the flexural strength and fracture toughness of the composites are modified. When the Si content is 1.82 wt %, the flexural strength and the fracture toughness reach the maximum value of 685.67 MPa and 9.02 MPa·m^1/2, respectively. The enhancing mechanism was also discussed.

Abstract: Full dense and highly pure TiAl/Ti5Si3 in situ composite was successfully synthesized by reactive synthesis from the powder mixtures of Ti, Al and Si. The reaction process was investigated in detail by the X-ray diffraction analysis (XRD) and differential scanning calorimetry (DSC). The microstructural characteristics of the TiAl/Ti5Si3 in situ composite were also studied by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the as fabricated composite possesses three phases, namely, TiAl, Ti3Al and Ti5Si3. The matrix phases are mainly equiaxed TiAl with a minor lamellar Ti3Al phase. Ti5Si3 particles with size less than 1 μm are distributed uniformly in matrix grains as a reinforcing phase.