Enhanced high-temperature tensile property by gradient twin structure of duplex high-Nb-containing TiAl alloy
Abstract
A pre-deformation process was employed for a TiAl alloy via high-temperature torsion, in which the stability of the constituent phases was tailored, resulting in enhanced hardening capability and ductility via a gradient microstructure. A sample with a pre-torsion of 360° exhibited a yield strength of 475 MPa and an ultimate tensile strength of 592 MPa, with a tensile ductility of 47% at 850 °C. The tensile properties were significantly enhanced compared with the as-forged sample, which exhibited values of 395 MPa, 494 MPa, and 4.6%, respectively. The physical mechanisms for the significant enhancement of the mechanical property of the TiAl alloys were studied in-depth via of transmission electron microscopy, electron-backscattered diffraction, and high-energy X-ray diffraction techniques. The high strength is mainly attributed to the twin structure formed during torsion, while high fracture elongation correlates to the recrystallization of the γ phase at twin-twin sections and the load partitioning regulated by a hierarchical microstructure. When the tensile micro-strains along the loading direction and transverse direction in the γ phase of the pre-deformed TiAl alloy, a higher mechanical performance was obtained. Moreover, the fracture mode of the pre-torsional tensile sample is a combination of pores and cleavage facets which resulted from themore »
- Authors:
-
[2];
- Univ. of Science and Technology, Beijing (China). State Key Lab. for Advanced Metals and Materials; China Jiliang Univ., Hangzhou (China)
- Univ. of Science and Technology, Beijing (China). State Key Lab. for Advanced Metals and Materials
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS), X-ray Science Division
- Beijing Inst. of Aeronautical Materials, Beijing (China). National Key Lab. of Science and Technology on Advanced High Temperature Structural Materials
- Publication Date:
- Research Org.:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Scientific User Facilities Division; National Natural Science Foundation of China (NNSFC)
- OSTI Identifier:
- 1505178
- Grant/Contract Number:
- AC02-06CH11357
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Acta Materialia
- Additional Journal Information:
- Journal Volume: 161; Journal Issue: C; Journal ID: ISSN 1359-6454
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; High Nb-containing TiAl alloys; High-energy X-ray diffraction; gradient structure; γ recrystallization
Citation Formats
Ding, Jie, Zhang, Minghe, Liang, Yongfeng, Ren, Yang, Dong, Chengli, and Lin, Junpin. Enhanced high-temperature tensile property by gradient twin structure of duplex high-Nb-containing TiAl alloy. United States: N. p., 2018.
Web. doi:10.1016/j.actamat.2018.09.007.
Ding, Jie, Zhang, Minghe, Liang, Yongfeng, Ren, Yang, Dong, Chengli, & Lin, Junpin. Enhanced high-temperature tensile property by gradient twin structure of duplex high-Nb-containing TiAl alloy. United States. doi:10.1016/j.actamat.2018.09.007.
Ding, Jie, Zhang, Minghe, Liang, Yongfeng, Ren, Yang, Dong, Chengli, and Lin, Junpin. Fri .
"Enhanced high-temperature tensile property by gradient twin structure of duplex high-Nb-containing TiAl alloy". United States. doi:10.1016/j.actamat.2018.09.007. https://www.osti.gov/servlets/purl/1505178.
@article{osti_1505178,
title = {Enhanced high-temperature tensile property by gradient twin structure of duplex high-Nb-containing TiAl alloy},
author = {Ding, Jie and Zhang, Minghe and Liang, Yongfeng and Ren, Yang and Dong, Chengli and Lin, Junpin},
abstractNote = {A pre-deformation process was employed for a TiAl alloy via high-temperature torsion, in which the stability of the constituent phases was tailored, resulting in enhanced hardening capability and ductility via a gradient microstructure. A sample with a pre-torsion of 360° exhibited a yield strength of 475 MPa and an ultimate tensile strength of 592 MPa, with a tensile ductility of 47% at 850 °C. The tensile properties were significantly enhanced compared with the as-forged sample, which exhibited values of 395 MPa, 494 MPa, and 4.6%, respectively. The physical mechanisms for the significant enhancement of the mechanical property of the TiAl alloys were studied in-depth via of transmission electron microscopy, electron-backscattered diffraction, and high-energy X-ray diffraction techniques. The high strength is mainly attributed to the twin structure formed during torsion, while high fracture elongation correlates to the recrystallization of the γ phase at twin-twin sections and the load partitioning regulated by a hierarchical microstructure. When the tensile micro-strains along the loading direction and transverse direction in the γ phase of the pre-deformed TiAl alloy, a higher mechanical performance was obtained. Moreover, the fracture mode of the pre-torsional tensile sample is a combination of pores and cleavage facets which resulted from the microstructure after torsion. Finally, the gradient twin structure approach in this study provides a strategy for developing TiAl alloys with exceptionally high-temperature tensile property, and the results of the micromechanical behavior-microstructure-property relationship may improve the understanding of the plastic deformation of TiAl alloys.},
doi = {10.1016/j.actamat.2018.09.007},
journal = {Acta Materialia},
number = C,
volume = 161,
place = {United States},
year = {2018},
month = {9}
}
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