Effect of forging on the microstructure and texture of a high Nb containing γ-TiAl alloy

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Hui TAO
  • Hui-Zhong LI
  • Li WANG
  • Yi-Xuan CHE
  • Yong-Hui CHEN
  • Xiao-Peng LIANG

Detail(s)

Original languageEnglish
Pages (from-to)1763-1773
Journal / PublicationJournal of Central South University
Volume31
Issue number6
Publication statusPublished - Jun 2024

Abstract

The effect of forging on the microstructure and texture evolution of a high Nb containing Ti-45Al-7Nb-0.3W (at.%) alloy was investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results show that the as-cast alloy is mainly composed of α2/γ lamellar colonies with a mean size of 70 µm, but the hot-forged pancake displays a near duplex microstructure (DP). Kinking and bending of lamellar colonies, deformation twinning and dynamic recrystallization (DRX) occur during hot forging. Meanwhile, dense dislocations in the β phase after forging suggest that the high-temperature β phase with a disordered structure is favorable for improving the hot-workability of the alloy. Unlike the common TiAl casting texture, the solidification process of the investigated as-cast alloy with high Nb content is completely via the β phase region, resulting in the formation of a <110>γ fiber texture where the <110>γ aligns parallel to the heat-flow direction. In comparison, the relatively strong <001> and weak <302> texture components in the as-forged alloy are attributed to the deformation twinning. After annealing, static recrystallization occurs at the twin boundary and intersections, which weakens the deformation texture. © Central South University 2024.

採用 X 射線衍射儀 (XRD)、 掃描電子顯微鏡(SEM)和透射電子顯微鏡 (TEM) 研究了鍛造對高鈮 Ti-45Al-7Nb-0.3W (at.%) 合金顯微組織和織構演變的影響. 結果表明: 鑄態合金主要由平均尺寸為 70 µm 的 α2/γ 層片組織組成, 而熱鍛態合金則呈現近雙態組織 (DP). 在熱鍛過程中, 合金發生了層片結構的扭折和彎曲、 變形孿晶和動態再結晶 (DRX). 同時, 鍛造後β相中密集的位錯表明, 具有無序結構的高溫 β 相有利於改善合金的熱加工性. 與常見的 TiAl 鑄造織構不同, 本研究中高鈮 TiAl 鑄態合金的凝固過程由於完全通過 β 單相區而形成了<110>γ 纖維織構, 即 <110>γ 晶向與熱流方向平行. 而鍛態合 金則表現出較強的 <001> 纖維織構和較弱的 <302> 纖維織構, 這可以歸因於變形孿晶. 退火後, 在孿晶界和孿晶交叉處發生靜態再結晶, 使變形織構減弱.

Research Area(s)

  • forging, high Nb containing γ-TiAl alloy, microstructure, texture, β phase

Citation Format(s)

Effect of forging on the microstructure and texture of a high Nb containing γ-TiAl alloy. / TAO, Hui; LI, Hui-Zhong; WANG, Li et al.
In: Journal of Central South University, Vol. 31, No. 6, 06.2024, p. 1763-1773.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review