Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size
As a kind of promising aerospace material, TiAl alloys need to withstand extreme conditions such as high-rate impact loads and high temperatures. The mechanism on the failure and fracture of TiAl alloys under extreme conditions is related with the microstructure, including phase and grain size. In t...
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Elsevier
2023-01-01
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Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785422018142 |
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author | Rui Liu Ye Jiao Yansong Guo Liu Chen Zhencheng Li Aixue Sha Fan Gao Pengwan Chen |
author_facet | Rui Liu Ye Jiao Yansong Guo Liu Chen Zhencheng Li Aixue Sha Fan Gao Pengwan Chen |
author_sort | Rui Liu |
collection | DOAJ |
description | As a kind of promising aerospace material, TiAl alloys need to withstand extreme conditions such as high-rate impact loads and high temperatures. The mechanism on the failure and fracture of TiAl alloys under extreme conditions is related with the microstructure, including phase and grain size. In the present research, two kinds of TiAl alloys tailored with different microstructures, near lamellar (NL) and near gamma (NG), were fabricated by thermo-mechanical treatment. Microstructural characterization was analyzed by XRD and EBSD. The dynamic behavior of the TiAl alloys under different temperatures ranging from 293 K–873 K was investigated by a split Hopkinson pressure bar. The strain rate sensitivity and temperature sensitivity was analyzed. The microstructural evolution was concerned to understand the failure mechanism of the two kinds of the TiAl alloys. The NG-TiAl had the homogeneous deformation with synergy effect between homogeneous equiaxed grain and lamellar structure, and no failure occurred in NG-TiAl. However, the NL-TiAl showed heterogeneous deformation with both “orange peel effect” and cracks, which was attributed to large equiaxed grain and brittle γ-lamellae with similar orientation. Further, the cracks were easily nucleated and propagated from the interface between γ-lamellae structures, especially in the γ-lamellae structures parallel with the loading direction. Finally, the modified Johnson–Cook constitutive model was proposed to describe the deformation behavior, in which both strain rate hardening and temperature softening terms were expressed as a function of strain and strain rate. |
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institution | Directory Open Access Journal |
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language | English |
last_indexed | 2024-04-10T20:17:20Z |
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spelling | doaj.art-0543a379206847c593efc1be088b38142023-01-26T04:45:31ZengElsevierJournal of Materials Research and Technology2238-78542023-01-0122292306Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain sizeRui Liu0Ye Jiao1Yansong Guo2Liu Chen3Zhencheng Li4Aixue Sha5Fan Gao6Pengwan Chen7State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, ChinaState Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, ChinaState Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, ChinaBeijing Institute of Aeronautical Materials, Beijing, 100095, China; Corresponding author.Beijing Institute of Aeronautical Materials, Beijing, 100095, ChinaBeijing Institute of Aeronautical Materials, Beijing, 100095, ChinaBeijing Institute of Aeronautical Materials, Beijing, 100095, ChinaState Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, 100081, China; Corresponding author.As a kind of promising aerospace material, TiAl alloys need to withstand extreme conditions such as high-rate impact loads and high temperatures. The mechanism on the failure and fracture of TiAl alloys under extreme conditions is related with the microstructure, including phase and grain size. In the present research, two kinds of TiAl alloys tailored with different microstructures, near lamellar (NL) and near gamma (NG), were fabricated by thermo-mechanical treatment. Microstructural characterization was analyzed by XRD and EBSD. The dynamic behavior of the TiAl alloys under different temperatures ranging from 293 K–873 K was investigated by a split Hopkinson pressure bar. The strain rate sensitivity and temperature sensitivity was analyzed. The microstructural evolution was concerned to understand the failure mechanism of the two kinds of the TiAl alloys. The NG-TiAl had the homogeneous deformation with synergy effect between homogeneous equiaxed grain and lamellar structure, and no failure occurred in NG-TiAl. However, the NL-TiAl showed heterogeneous deformation with both “orange peel effect” and cracks, which was attributed to large equiaxed grain and brittle γ-lamellae with similar orientation. Further, the cracks were easily nucleated and propagated from the interface between γ-lamellae structures, especially in the γ-lamellae structures parallel with the loading direction. Finally, the modified Johnson–Cook constitutive model was proposed to describe the deformation behavior, in which both strain rate hardening and temperature softening terms were expressed as a function of strain and strain rate.http://www.sciencedirect.com/science/article/pii/S2238785422018142TiAl alloysMicrostructureDynamic behaviorFailure modethe modified Johnson–Cook constitutive model |
spellingShingle | Rui Liu Ye Jiao Yansong Guo Liu Chen Zhencheng Li Aixue Sha Fan Gao Pengwan Chen Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size Journal of Materials Research and Technology TiAl alloys Microstructure Dynamic behavior Failure mode the modified Johnson–Cook constitutive model |
title | Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size |
title_full | Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size |
title_fullStr | Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size |
title_full_unstemmed | Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size |
title_short | Dynamic behavior and microstructural evolution of TiAl alloys tailored via phase and grain size |
title_sort | dynamic behavior and microstructural evolution of tial alloys tailored via phase and grain size |
topic | TiAl alloys Microstructure Dynamic behavior Failure mode the modified Johnson–Cook constitutive model |
url | http://www.sciencedirect.com/science/article/pii/S2238785422018142 |
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