TiAl合金有序ω相和正交相相变规律研究进展-中国材料进展

文章信息/Info

Title:: Progress in the Phase Transformation Mechanisms of Ordered ω and Orthorhombic Phases in TiAl Alloys

作者:: 宋霖1; 张铁邦1; 林均品2; （1.西北工业大学凝固技术国家重点实验室，陕西西安 710072) （2.北京科技大学新金属材料国家重点实验室，北京 100083）

Author(s):: SONG Lin1; ZHANG Tiebang1; LIN Junpin2; （1. State Key Laboratory of Solidification Progressing, Northwestern Polytechnical University, Xian 710072, China）（2. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China)

Keywords:: TiAl alloys; ordered ω phase; orthorhombic phase; phase transformation mechanisms; microstructure

摘要:: 轻质高强TiAl合金作为用于先进航空发动机减重的高温结构材料，近年来表现出了巨大的市场前景。含有一定量β相的变形TiAl合金是未来合金研发的重要方向。为在高温下充分利用一定量的β相进行热变形，β相稳定元素的加入使得合金在中温区，也即服役温度区间内出现多种复杂相变，如ωo相演变、正交相演变及亚稳α2相的分解等。这些相变对合金的显微组织稳定性具有重要影响，从而深刻影响合金的长时服役性能。另外，外加应力对这些中温相变也会产生明显的影响，加速合金的显微组织演变。总结了近年来关于ωo相和正交相的研究成果，主要从显微组织分析角度对βo相区域内相变、ωo相和正交相在α2相内析出以及应力对上述相变的影响规律等几个方面进行了综述，总结了上述相变对TiAl合金的中温显微组织稳定性的影响，并对未来的研究方向进行了展望。

Abstract:: Light-weight high-strength TiAl alloys have gained great expectation in the aerospace market as high-temperature structural materials for the weight reduction of advanced aeroengines. Wrought TiAl alloys containing certain amount of β phase are important categories for future development of these alloys. In order to facilitate hot deformation, β phase is stabilized by β stabilizing elements, leading to a number of complex phase transformations at intermediate temperatures, i.e., the application temperatures, such as ωo and orthorhombic phase transformations as well as the decomposition of metastable α2 phase. These phase transformations have crucial effects on the stability of the microstructures, which are essentially related to the long-term service properties of the alloys. On the other hand, the applied stress also directly affects these phase transformations at intermediate temperatures, accelerating the evolution of the microstructures. In this article, the recent researches on the ωo and orthorhombic phases are summarized in perspective of microstructure characterization. Mechanisms of the phase transformations in the βo phase region, the precipitation of ωo and orthorhombic phases from α2 phase as well as the effects of stress on these phase transformations are reviewed. The effects of the above-mentioned phase transformations on the microstructure stability are summarized and the future research directions are prospected.