Fabrication and Mechanical Properties of In Situ Synthesized Ti₂AlN/TiAl Composite

TiAl matrix composites reinforced with Ti₂AlN were fabricated by in situ reactive method of powder metallurgy. Microstructures, bending properties at room temperature and compressive properties at elevated temperatures were investigated in contrast with those of TiAl alloy. The results reveal that the microstructure of TiAl matrix is significantly refined due to the synthesis of Ti₂AlN. 15 vol.%Ti₂AlN/TiAl exhibits excellent bending properties at room temperature, with bending strength of 753 MPa and fracture strain of 0.74%, which are 24.3 and 19.7% higher than those of TiAl alloy. The compressive strength of Ti₂AlN/TiAl is markedly improved in comparison to that of TiAl alloy at elevated temperatures. Noticeably, the compressive strength of 15 and 35 vol.%Ti₂AlN/TiAl increases by 67.4 and 58.7% at 1000 °C, respectively. The remarkable enhancement of mechanical performance is mainly due to the noteworthy refinement of TiAl matrix and the efficient obstruction of Ti₂AlN particles to crack propagation, as well as the effective load-carrying role of Ti₂AlN with high elastic modulus.