中文摘要：

高Nb-TiAl合金具有高比强和优异的高温性能,是TiAl合金向800℃以上应用发展的重要方向,其定向组织合金作为叶片材料在高推重比发动机中具有巨大的应用潜力。以传统TiAl合金定向凝固为背景论述了高Nb-TiAl合金定向凝固的研究现状。首先介绍了定向凝固方法和模壳材料发展,然后对高Nb-TiAl合金定向凝固宏观组织、界面形态和片层特征控制进行了评述,接着简要阐述了冷坩埚定向凝固制备高Nb-TiAl合金的相关工作,进一步对定向组织高Nb-TiAl合金的力学性能进行了分析。最后,展望了高Nb-TiAl合金定向凝固的发展方向。

英文摘要：

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 °C. 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.