文章信息/Info

Title:

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

文章編號:

1674-3962(2020)09-0634-08

作者:

宋霖1; 張鐵邦1; 林均品2

（1.西北工業大學 凝固技術國家重點實驗室，陜西 西安 710072) （2.北京科技大學 新金屬材料國家重點實驗室，北京 100083）

Author(s):

SONG Lin1; ZHANG Tiebang1; LIN Junpin2

（1. State Key Laboratory of Solidification Progressing, Northwestern Polytechnical University, Xi�餫n 710072, China）（2. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China)

關鍵詞:

TiAl合金; 有序ω相; 正交相; 相變規律; 顯微組織

Keywords:

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

分類號:

TG146.23

DOI:

10.7502/j.issn.1674-3962.201908027

文獻標志碼:

A

摘要:

輕質高強TiAl合金作為用于先進航空發動機減重的高溫結構材料，近年來表現出了巨大的市場前景。含有一定量β相的變形TiAl合金是未來合金研發的重要方向。為在高溫下充分利用一定量的β相進行熱變形，β相穩定元素的加入使得合金在中溫區，也即服役溫度區間內出現多種復雜相變，如ωo相演變、正交相演變及亞穩α2相的分解等。這些相變對合金的顯微組織穩定性具有重要影響，從而深刻影響合金的長時服役性能。另外，外加應力對這些中溫相變也會產生明顯的影響，加速合金的顯微組織演變。總結了近年來關于ωo相和正交相的研究成果，主要從顯微組織分析角度對βo相區域內相變、ωo相和正交相在α2相內析出以及應力對上述相變的影響規律等幾個方面進行了綜述，總結了上述相變對TiAl合金的中溫顯微組織穩定性的影響，并對未來的研究方向進行了展望。

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.