中国物理B ›› 2026, Vol. 35 ›› Issue (7): 76401-076401.doi: 10.1088/1674-1056/ae5a10

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Plastic enhancement mechanism of γ-TiAl//α2-Ti3Al lamellar structure via AlTi antisite defect

Lei Sheng(盛磊)1,†, Xiong Zhou(周雄)1,†, Qiran Gong(龚琪然)2, Zhongtao Lu(陆忠涛)2, Pengcheng Zhai(翟鹏程)1,2, Xiege Huang(黄写格)2, Shiping Wang(王世平)2, Wenjuan Li(李文娟)2, Xiaobin Feng(冯骁斌)2, and Guodong Li(李国栋)1,2,‡   

  1. 1 State Key Laboratory of Light Superalloys, Wuhan University of Technology, Wuhan 430070, China;
    2 Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, School of Physics and Mechanics, Wuhan University of Technology, Wuhan 430070, China
  • 收稿日期:2026-02-09 修回日期:2026-03-20 接受日期:2026-04-01 发布日期:2026-07-21
  • 通讯作者: Guodong Li E-mail:guodonglee@whut.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 92163215, 92163212, 92463301, and 92463309).

Plastic enhancement mechanism of γ-TiAl//α2-Ti3Al lamellar structure via AlTi antisite defect

Lei Sheng(盛磊)1,†, Xiong Zhou(周雄)1,†, Qiran Gong(龚琪然)2, Zhongtao Lu(陆忠涛)2, Pengcheng Zhai(翟鹏程)1,2, Xiege Huang(黄写格)2, Shiping Wang(王世平)2, Wenjuan Li(李文娟)2, Xiaobin Feng(冯骁斌)2, and Guodong Li(李国栋)1,2,‡   

  1. 1 State Key Laboratory of Light Superalloys, Wuhan University of Technology, Wuhan 430070, China;
    2 Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics, School of Physics and Mechanics, Wuhan University of Technology, Wuhan 430070, China
  • Received:2026-02-09 Revised:2026-03-20 Accepted:2026-04-01 Published:2026-07-21
  • Contact: Guodong Li E-mail:guodonglee@whut.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 92163215, 92163212, 92463301, and 92463309).

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摘要： Polysynthetically twinned (PST) TiAl consisting of a two-phase ($\gamma $ and $\alpha_{2}$) lamellar structure is an effective microstructural strategy for enhancing mechanical properties, and Al-rich composition is a common phenomenon. However, the effect of the Al$_{\rm Ti}$ antisite defect on the deformation mechanism of the $\gamma $-TiAl//$\alpha_{2}$-Ti$_{3}$Al lamellar structure remains unclear. The deformation mechanisms of the $\gamma $//$\alpha_{2}$ lamellar structure under pure shear mainly involve three sequential stages: (i) The weaker Ti-Ti and Al-Al metallic bonds induce the "phase boundary (PB) transition". (ii) The stronger Ti-Ti and Al-Al metallic bonds induce the "orientation transition" in $\gamma $-TiAl. (iii) The strongest Ti-Al covalent bonds induce the "phase transition" in $\alpha_{2}$-Ti$_{3}$Al. Introducing an Al$_{\rm Ti}$ antisite defect can weaken the original Ti-Al covalent bonds while generating new Al-Al metallic bonds, which provides an additional slip path and results in excellent enhancement of plasticity. The competition mechanisms between these plastic behaviors can be well explained through generalized stacking fault energy (GSFE) calculations.

关键词: density-functional theory, TiAl alloys, antisite defects, intrinsic mechanical properties

Abstract: Polysynthetically twinned (PST) TiAl consisting of a two-phase ($\gamma $ and $\alpha_{2}$) lamellar structure is an effective microstructural strategy for enhancing mechanical properties, and Al-rich composition is a common phenomenon. However, the effect of the Al$_{\rm Ti}$ antisite defect on the deformation mechanism of the $\gamma $-TiAl//$\alpha_{2}$-Ti$_{3}$Al lamellar structure remains unclear. The deformation mechanisms of the $\gamma $//$\alpha_{2}$ lamellar structure under pure shear mainly involve three sequential stages: (i) The weaker Ti-Ti and Al-Al metallic bonds induce the "phase boundary (PB) transition". (ii) The stronger Ti-Ti and Al-Al metallic bonds induce the "orientation transition" in $\gamma $-TiAl. (iii) The strongest Ti-Al covalent bonds induce the "phase transition" in $\alpha_{2}$-Ti$_{3}$Al. Introducing an Al$_{\rm Ti}$ antisite defect can weaken the original Ti-Al covalent bonds while generating new Al-Al metallic bonds, which provides an additional slip path and results in excellent enhancement of plasticity. The competition mechanisms between these plastic behaviors can be well explained through generalized stacking fault energy (GSFE) calculations.

Key words: density-functional theory, TiAl alloys, antisite defects, intrinsic mechanical properties

中图分类号:  (Metals and alloys)

  • 64.70.kd
31.15.es (Applications of density-functional theory (e.g., to electronic structure and stability; defect formation; dielectric properties, susceptibilities; viscoelastic coefficients; Rydberg transition frequencies)) 61.46.-w (Structure of nanoscale materials)