Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy

This study investigates the evolution mechanism of the fan-type γ′ structure and its effect on serrated grain boundary in GH4742 superalloy under different cooling rates. The formation mechanism of the fan-type γ′ structure and the mechanism of serrated grain boundary in GH4742 superalloy are discus...

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Main Authors: Qiang Tian, Wenwen Zhang, Hucheng Li, Yunlong Liu, Tonggang Lu, Jinhui Du, Xingang Liu, Kaiyao Wang
Format: Article
Language:English
Published: Elsevier 2025-03-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425003540
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author Qiang Tian
Wenwen Zhang
Hucheng Li
Yunlong Liu
Tonggang Lu
Jinhui Du
Xingang Liu
Kaiyao Wang
author_facet Qiang Tian
Wenwen Zhang
Hucheng Li
Yunlong Liu
Tonggang Lu
Jinhui Du
Xingang Liu
Kaiyao Wang
author_sort Qiang Tian
collection DOAJ
description This study investigates the evolution mechanism of the fan-type γ′ structure and its effect on serrated grain boundary in GH4742 superalloy under different cooling rates. The formation mechanism of the fan-type γ′ structure and the mechanism of serrated grain boundary in GH4742 superalloy are discussed. The results show that as the cooling rate decreases, the size of the fan-type γ′ structure increases, exhibiting significant preferential growth characteristics during the process. When the cooling rate is below 120 °C/h, both the size and the number of the fan-type γ′ structure branches increase sharply. The size grows from 2.5 μm at 120 °C/h to 45.6 μm at 1 °C/h, and the number of branches increases from 7 at 120 °C/h to 40 at 1 °C/h. Furthermore, the fan-type γ′ structure shows different characteristics in terms of serrated grain boundary at various cooling rates. When the cooling rate is higher than 120 °C/h, the fan-type γ′ structure mainly manifests a pinning mechanism, resulting in small amplitude fluctuations of the serrated grain boundary. However, when the cooling rate drops below 120 °C/h, the growth mechanism becomes dominant, leading to larger cellular structures and more twisted serrated grain boundaries. Consequently, as the cooling rate decreases, the amplitude of the serrated grain boundaries increases from 1.4 μm to 50.4 μm, and the wavelength increases from 3.5 μm to 262.5 μm. The findings of this study are of significant importance for the microstructure optimization and performance regulation of GH4742 superalloy.
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issn 2238-7854
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publishDate 2025-03-01
publisher Elsevier
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series Journal of Materials Research and Technology
spelling doaj-art-9dc8d366e28d49f990181aa02de977c22025-08-20T03:11:43ZengElsevierJournal of Materials Research and Technology2238-78542025-03-01354352436710.1016/j.jmrt.2025.02.107Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloyQiang Tian0Wenwen Zhang1Hucheng Li2Yunlong Liu3Tonggang Lu4Jinhui Du5Xingang Liu6Kaiyao Wang7High Temperature Materials Research Division, Central Iron & Steel Research Institute, Beijing, 100081, ChinaCollege of Mechanical Engineering, Yanshan University, Qinhuangdao, 066004, Hebei, China; Corresponding author.College of Mechanical Engineering, Yanshan University, Qinhuangdao, 066004, Hebei, ChinaCollege of Mechanical Engineering, Yanshan University, Qinhuangdao, 066004, Hebei, ChinaCollege of Mechanical Engineering, Yanshan University, Qinhuangdao, 066004, Hebei, ChinaHigh Temperature Materials Research Division, Central Iron & Steel Research Institute, Beijing, 100081, ChinaCollege of Mechanical Engineering, Yanshan University, Qinhuangdao, 066004, Hebei, ChinaGraduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, 739-8527, JapanThis study investigates the evolution mechanism of the fan-type γ′ structure and its effect on serrated grain boundary in GH4742 superalloy under different cooling rates. The formation mechanism of the fan-type γ′ structure and the mechanism of serrated grain boundary in GH4742 superalloy are discussed. The results show that as the cooling rate decreases, the size of the fan-type γ′ structure increases, exhibiting significant preferential growth characteristics during the process. When the cooling rate is below 120 °C/h, both the size and the number of the fan-type γ′ structure branches increase sharply. The size grows from 2.5 μm at 120 °C/h to 45.6 μm at 1 °C/h, and the number of branches increases from 7 at 120 °C/h to 40 at 1 °C/h. Furthermore, the fan-type γ′ structure shows different characteristics in terms of serrated grain boundary at various cooling rates. When the cooling rate is higher than 120 °C/h, the fan-type γ′ structure mainly manifests a pinning mechanism, resulting in small amplitude fluctuations of the serrated grain boundary. However, when the cooling rate drops below 120 °C/h, the growth mechanism becomes dominant, leading to larger cellular structures and more twisted serrated grain boundaries. Consequently, as the cooling rate decreases, the amplitude of the serrated grain boundaries increases from 1.4 μm to 50.4 μm, and the wavelength increases from 3.5 μm to 262.5 μm. The findings of this study are of significant importance for the microstructure optimization and performance regulation of GH4742 superalloy.http://www.sciencedirect.com/science/article/pii/S2238785425003540GH4742 superalloyγ′ precipitateSerrated grain boundaryFan-type γ′ structureCooling rates
spellingShingle Qiang Tian
Wenwen Zhang
Hucheng Li
Yunlong Liu
Tonggang Lu
Jinhui Du
Xingang Liu
Kaiyao Wang
Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy
Journal of Materials Research and Technology
GH4742 superalloy
γ′ precipitate
Serrated grain boundary
Fan-type γ′ structure
Cooling rates
title Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy
title_full Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy
title_fullStr Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy
title_full_unstemmed Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy
title_short Formation mechanism of serrated grain boundary caused by different morphologies of γ′ precipitates in GH4742 superalloy
title_sort formation mechanism of serrated grain boundary caused by different morphologies of γ precipitates in gh4742 superalloy
topic GH4742 superalloy
γ′ precipitate
Serrated grain boundary
Fan-type γ′ structure
Cooling rates
url http://www.sciencedirect.com/science/article/pii/S2238785425003540
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