TiAl合金在航空航天、能源与汽车材料领域有巨大的潜在应用前景。定向凝固技术的应用可以避开传统的变形加工工艺，获得优异的取向性能，已成为TiAl合金加工和制备工艺的重要技术手段之一。包晶TiAl合金的晶体取向控制难度大是阻碍定向凝固TiAl合金发展的重大障碍。本项目在前期定向凝固TiAl-Nb三元合金包晶晶体取向研究的基础上，提出结合组织遗传性和包晶相变过程精确控制定向凝固TiAl-Nb合金晶体取向的创新思路。深入研究TiAlNb三元系统的定向凝固包晶相变过程的调控机制，明确包晶相变过程与产物特征对定向凝固组织遗传特性的影响，揭示包晶合金定向凝固组织遗传性本质，阐明定向凝固组织遗传性与包晶相变过程的相互作用机理，为TiAl-Nb合金系定向凝固包晶晶体取向控制提供科学基础及理论依据，促进定向凝固多元TiAl合金的工业化应用。

TiAl alloys have great potential application prospect in the fields of aviation and aerospace, energy and automobile materials. The directional solidification (DS) technique is developed to keep away from the conventional forging processing and to achieve the improved properties in preferred orientation, which has became an important technique for manufacturing and processing of TiAl alloys. However, the difficulty to control the crystal orientation of the peritectic TiAl alloy is a major obstacle to the development of the directionally solidified TiAl alloys. Based on the previous study on the peritectic crystal oriention in TiAl-Nb ternary alloys, this project proposes an innovated way to control the crystal orientation through combined controlling of the microstructure inheritance with the peritectic transition. The adjustment mechanism on peritectic phase transition will be systematically investigated in ternary TiAlNb system, and influences of the peritectic transition procedure and its products on the microstructure inheritance will also be investigated to disclose the inheritance nature of directional solidification in peritectic alloy, evetually to find out the interaction between the microstructure inheritance and the peritectic transition. It will provide scientific and theoretical basis for controlling the peritectic crystal orientation in TiAl-Nb alloys and promote the development for industrial application of directionally solidified multiple TiAl alloys.