Effect of Heat Treatment on Microstructure and Mechanical Properties of TiAl-Based Alloy

The effect of different heat treatment process on microstructure and mechanical property of casting Ti-44Al-4Nb-4Zr-1B alloy was investigated. The results indicate that High temperature strength than the room temperature increased by about 130 similar to 200MPa. High elongation at break relative to the room temperature is greatly improved. In the two-phase region (alpha+gamma) for a long time after then slow cooling and cyclic heat treatment effect is obvious. But the tensile properties and Stress rupture life has little effect. TiAl-based intermetallic compound has become an important novel high-temperature structural material. It has a wide application prospect and development potential for its advantages such as low density, high strength at high temperature, high hardness and good oxidation resistance. However, general cast structure of TiAl-based alloy is a coarse alpha(2)/gamma lamellar structure. Numerous studies have shown that we have to get uniform and tiny lamellar structure or dual phase structure to make the alloy obtain good mechanical property. In this paper the influence of different heat treatment processes on casting microstructure of Ti-44Al-4Nb-4Zr-1B ( at. %, atomic fraction) was studied. And then seek the approach of heat treatment which can effectively refine casting structure of TiAl-based alloy, and meanwhile further improve its mechanical properties.