Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties

In this study, friction stir welding (FSW) of 2-mm-thick Ti–6Al–4V alloy plates was performed using a newly designed friction tool—and the effect of rotation speed and welding speed on microstructure and mechanical properties of the joints were investigated. A simulation model for FSW temperature fi...

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Main Authors: Junping Li, Fujun Cao, Yifu Shen
Format: Article
Language:English
Published: MDPI AG 2020-07-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/10/7/940
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author Junping Li
Fujun Cao
Yifu Shen
author_facet Junping Li
Fujun Cao
Yifu Shen
author_sort Junping Li
collection DOAJ
description In this study, friction stir welding (FSW) of 2-mm-thick Ti–6Al–4V alloy plates was performed using a newly designed friction tool—and the effect of rotation speed and welding speed on microstructure and mechanical properties of the joints were investigated. A simulation model for FSW temperature field calculation was developed, and the effect of rotation speed and welding speed on the temperature field was investigated by experimental and numeric methods. The results show that the rotation speed has a dominant effect on peak temperature, while welding speed determines the dwell time of the weld exposed to high temperatures. In addition, the influence of process parameters on the microstructure of the joints was investigated using optical and scanning electron microscopy. The results revealed that there was a phase transformation in the stir zone during welding. The final microstructure of the stir zone was fully lamellar (α + β) structure, and the heat affection zone had a bimodal microstructure consisting of prior equiaxed α and lamellar (α + β) structure. Both rotation speed and welding speed affect the grain size of the weld. Lower peak temperature with decreasing spindle speed and/or shorter dwell time with increasing feed rate could produce finer grains in the stir zone of the joints, thereby could lead to higher microhardness value and the tensile strength of the joints.
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spelling doaj.art-48976264377d4d048abfef54342d9ac32023-11-20T06:36:49ZengMDPI AGMetals2075-47012020-07-0110794010.3390/met10070940Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical PropertiesJunping Li0Fujun Cao1Yifu Shen2College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Jiangjun Road, Nanjing 211106, ChinaCollege of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Jiangjun Road, Nanjing 211106, ChinaCollege of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, 29 Jiangjun Road, Nanjing 211106, ChinaIn this study, friction stir welding (FSW) of 2-mm-thick Ti–6Al–4V alloy plates was performed using a newly designed friction tool—and the effect of rotation speed and welding speed on microstructure and mechanical properties of the joints were investigated. A simulation model for FSW temperature field calculation was developed, and the effect of rotation speed and welding speed on the temperature field was investigated by experimental and numeric methods. The results show that the rotation speed has a dominant effect on peak temperature, while welding speed determines the dwell time of the weld exposed to high temperatures. In addition, the influence of process parameters on the microstructure of the joints was investigated using optical and scanning electron microscopy. The results revealed that there was a phase transformation in the stir zone during welding. The final microstructure of the stir zone was fully lamellar (α + β) structure, and the heat affection zone had a bimodal microstructure consisting of prior equiaxed α and lamellar (α + β) structure. Both rotation speed and welding speed affect the grain size of the weld. Lower peak temperature with decreasing spindle speed and/or shorter dwell time with increasing feed rate could produce finer grains in the stir zone of the joints, thereby could lead to higher microhardness value and the tensile strength of the joints.https://www.mdpi.com/2075-4701/10/7/940friction stir weldingTi–6Al–4Vtemperaturemicrostructuremechanical property
spellingShingle Junping Li
Fujun Cao
Yifu Shen
Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties
Metals
friction stir welding
Ti–6Al–4V
temperature
microstructure
mechanical property
title Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties
title_full Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties
title_fullStr Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties
title_full_unstemmed Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties
title_short Effect of Welding Parameters on Friction Stir Welded Ti–6Al–4V Joints: Temperature, Microstructure and Mechanical Properties
title_sort effect of welding parameters on friction stir welded ti 6al 4v joints temperature microstructure and mechanical properties
topic friction stir welding
Ti–6Al–4V
temperature
microstructure
mechanical property
url https://www.mdpi.com/2075-4701/10/7/940
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AT fujuncao effectofweldingparametersonfrictionstirweldedti6al4vjointstemperaturemicrostructureandmechanicalproperties
AT yifushen effectofweldingparametersonfrictionstirweldedti6al4vjointstemperaturemicrostructureandmechanicalproperties