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(hào):

1674-3962(2020)09-0634-08

作者:

宋霖1; 張鐵邦1; 林均品2

（1.西北工業(yè)大學(xué) 凝固技術(shù)國家重點(diǎn)實(shí)驗(yàn)室，陜西 西安 710072) （2.北京科技大學(xué) 新金屬材料國家重點(diǎn)實(shí)驗(yàn)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(guān)鍵詞:

TiAl合金; 有序ω相; 正交相; 相變規(guī)律; 顯微組織

Keywords:

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

分類號(hào):

TG146.23

DOI:

10.7502/j.issn.1674-3962.201908027

文獻(xiàn)標(biāo)志碼:

A

摘要:

輕質(zhì)高強(qiáng)TiAl合金作為用于先進(jìn)航空發(fā)動(dòng)機(jī)減重的高溫結(jié)構(gòu)材料，近年來表現(xiàn)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(fā)的重要方向。為在高溫下充分利用一定量的β相進(jìn)行熱變形，β相穩(wěn)定元素的加入使得合金在中溫區(qū)，也即服役溫度區(qū)間內(nèi)出現(xiàn)多種復(fù)雜相變，如ωo相演變、正交相演變及亞穩(wěn)α2相的分解等。這些相變對(duì)合金的顯微組織穩(wěn)定性具有重要影響，從而深刻影響合金的長時(shí)服役性能。另外，外加應(yīng)力對(duì)這些中溫相變也會(huì)產(chǎn)生明顯的影響，加速合金的顯微組織演變�？偨Y(jié)了近年來關(guān)于ωo相和正交相的研究成果，主要從顯微組織分析角度對(duì)βo相區(qū)域內(nèi)相變、ωo相和正交相在α2相內(nèi)析出以及應(yīng)力對(duì)上述相變的影響規(guī)律等幾個(gè)方面進(jìn)行了綜述，總結(jié)了上述相變對(duì)TiAl合金的中溫顯微組織穩(wěn)定性的影響，并對(duì)未來的研究方向進(jìn)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.