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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Main Authors: Rui Liu, Ye Jiao, Yansong Guo, Liu Chen, Zhencheng Li, Aixue Sha, Fan Gao, Pengwan Chen
Format: Article
Language:English
Published: Elsevier 2023-01-01
Series:Journal of Materials Research and Technology
Subjects:
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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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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