Recent Progress in High Temperature TiAl Alloys

Conventional cast TiAl alloys have been used for the GEnx engine. However, the conventional TiAl alloys are not strong enough for applications at higher temperatures. TiAl alloys have been developed into two categories: conventional TiAl and high temperature TiAl (high niobium containing) alloys. These state-of-the-art alloys have great advantage that the service temperature is 60-100 °C higher than that of conventional TiAl alloys. The paper discussed the relationships among composition, microstructure and properties for high temperature TiAl alloys, including the phase relationship with high Nb contents, the high temperature strengthening mechanisms of Nb, Al, excellent oxidation resistance at high temperature, especially focusing the new technology for the fabrication and processing of pilot ingots.