Research progress and prospect of high Nb containing TiAl alloys directional solidification

High Nb containing TiAl alloys possess high specific strength and excellent performance at evaluated temperature, which is the significant development of TiAl intermetallics for applying up to 800℃. The directionally solidified high Nb-TiAl alloys have huge potential on the blade materials in the next generation aviation engine with a high thrust-weight ratio. Based on the directional solidification (DS) of conventional TiAl alloys, the current status of DS high Nb-TiAl alloys was discussed in this paper. Firstly, the DS methods and mould materials for directionally solidified high Nb-TiAl alloys were introduced. Then the macrostructure, the interface morphology and the α₂/γ lamella of directionally solidified high Nb-TiAl alloys were elaborated. Furthermore, the cold crucible directional solidification of high Nb-TiAl alloys was presented and the mechanical properties of TiAl alloys were analyzed. Last, the prospect of DS high Nb-TiAl alloys was outlook.