High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism

TiAl alloys are lightweight, high-strength, and have good mechanical properties at elevated temperatures, rendering them appealing for high-temperature applications. However, their difficult processing, and limited ductility at ambient temperatures have hindered their widespread application. Here, w...

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Main Authors: Yuan Ye, Yuyong Chen, Yu Zhang, Shuzhi Zhang, Jianfei Sun
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Materials & Design
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Online Access:http://www.sciencedirect.com/science/article/pii/S0264127525002485
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author Yuan Ye
Yuyong Chen
Yu Zhang
Shuzhi Zhang
Jianfei Sun
author_facet Yuan Ye
Yuyong Chen
Yu Zhang
Shuzhi Zhang
Jianfei Sun
author_sort Yuan Ye
collection DOAJ
description TiAl alloys are lightweight, high-strength, and have good mechanical properties at elevated temperatures, rendering them appealing for high-temperature applications. However, their difficult processing, and limited ductility at ambient temperatures have hindered their widespread application. Here, we report fabrication of a Ti-43Al-9 V-0.3Y alloy with a novel lamellar-network two-scale structure comprising an inner α2/γ lamellar colony + outer β0/γ phases via semi-solid forging process. The formation of this lamellar-network two-scale structure is elucidated from the perspective of the solute diffusion and redistribution occurring, and occurs due to liquid segregation and a non-equilibrium transition of L → β(β0) + α at late solidification. Compared to the as-cast alloy, the semi-solid forged alloy exhibits significant increases in elongation and tensile strength at room temperature and 800°C. The high density of dislocations and mechanical twins in the β0/γ phases and special α2/γ lamellae during tensile deformation effectively release the plastic deformation potential of the TiAl alloy at room temperature. Moreover, the abundant nano-twins in the β0/γ phase and γ dynamic recrystallization behavior at 800 ℃ significantly enhance the high-temperature plasticity. This approach and microstructure offer a promising solution to the engineering challenges posed by the low room-temperature ductility and limited hot-working ability of TiAl alloys.
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spelling doaj-art-ba10562c19de4a83adc1aa9ddf88488c2025-08-20T03:22:04ZengElsevierMaterials & Design0264-12752025-05-0125311382810.1016/j.matdes.2025.113828High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanismYuan Ye0Yuyong Chen1Yu Zhang2Shuzhi Zhang3Jianfei Sun4School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaSchool of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; The National Key Laboratory for Precision Hot Forming of Metals, Harbin 150001, China; Corresponding authors.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; Corresponding authors.State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China; Corresponding authors.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, ChinaTiAl alloys are lightweight, high-strength, and have good mechanical properties at elevated temperatures, rendering them appealing for high-temperature applications. However, their difficult processing, and limited ductility at ambient temperatures have hindered their widespread application. Here, we report fabrication of a Ti-43Al-9 V-0.3Y alloy with a novel lamellar-network two-scale structure comprising an inner α2/γ lamellar colony + outer β0/γ phases via semi-solid forging process. The formation of this lamellar-network two-scale structure is elucidated from the perspective of the solute diffusion and redistribution occurring, and occurs due to liquid segregation and a non-equilibrium transition of L → β(β0) + α at late solidification. Compared to the as-cast alloy, the semi-solid forged alloy exhibits significant increases in elongation and tensile strength at room temperature and 800°C. The high density of dislocations and mechanical twins in the β0/γ phases and special α2/γ lamellae during tensile deformation effectively release the plastic deformation potential of the TiAl alloy at room temperature. Moreover, the abundant nano-twins in the β0/γ phase and γ dynamic recrystallization behavior at 800 ℃ significantly enhance the high-temperature plasticity. This approach and microstructure offer a promising solution to the engineering challenges posed by the low room-temperature ductility and limited hot-working ability of TiAl alloys.http://www.sciencedirect.com/science/article/pii/S0264127525002485TiAl alloySemi-solid forgingMechanical propertiesNon-equilibrium solidification
spellingShingle Yuan Ye
Yuyong Chen
Yu Zhang
Shuzhi Zhang
Jianfei Sun
High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism
Materials & Design
TiAl alloy
Semi-solid forging
Mechanical properties
Non-equilibrium solidification
title High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism
title_full High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism
title_fullStr High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism
title_full_unstemmed High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism
title_short High-performing TiAl alloy with lamellar-network two-scale structure via semi-solid forging and its non-equilibrium solidification mechanism
title_sort high performing tial alloy with lamellar network two scale structure via semi solid forging and its non equilibrium solidification mechanism
topic TiAl alloy
Semi-solid forging
Mechanical properties
Non-equilibrium solidification
url http://www.sciencedirect.com/science/article/pii/S0264127525002485
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AT shuzhizhang highperformingtialalloywithlamellarnetworktwoscalestructureviasemisolidforginganditsnonequilibriumsolidificationmechanism
AT jianfeisun highperformingtialalloywithlamellarnetworktwoscalestructureviasemisolidforginganditsnonequilibriumsolidificationmechanism