Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment

Aero-engine turbine vanes made from directionally solidified nickel-based superalloys often fail with crack formation from the external wall of cooling channels. Therefore, this study simulates the compressive load on the external wall of the vane and conducts a sequence of creep–fatigue evaluations...

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Main Authors: Anping Long, Xiaoshan Liu, Lei Xiao, Gaoxiang Zhang, Jiangying Xiong, Ganjiang Feng, Jianzheng Guo, Rutie Liu
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/5/429
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author Anping Long
Xiaoshan Liu
Lei Xiao
Gaoxiang Zhang
Jiangying Xiong
Ganjiang Feng
Jianzheng Guo
Rutie Liu
author_facet Anping Long
Xiaoshan Liu
Lei Xiao
Gaoxiang Zhang
Jiangying Xiong
Ganjiang Feng
Jianzheng Guo
Rutie Liu
author_sort Anping Long
collection DOAJ
description Aero-engine turbine vanes made from directionally solidified nickel-based superalloys often fail with crack formation from the external wall of cooling channels. Therefore, this study simulates the compressive load on the external wall of the vane and conducts a sequence of creep–fatigue evaluations at 980 °C to investigate the creep–fatigue damage mechanisms of a directionally solidified superalloy and to assess its life. It is found that at low strain ranges, creep damage is dominant, with creep cavities forming inside the specimen and fatigue sources mostly distributed in the specimen interior. As the strain range increases, the damage mechanism transitions from creep-dominated to creep–fatigue coupled damage, with cracks nucleating preferentially on the surface and exhibiting a characteristic of multiple fatigue sources. In the longitudinal (L) specimen, dislocations in multiple orientations of the {111}<110> slip system are activated simultaneously, interacting within the γ channels to form dislocation networks, and dislocations shear through the γ′ phase via antiphase boundary (APB) pairs. In the transverse (T) specimen, stacking intrinsic stacking faults (SISFs) accumulate within the limited {111}<112> slip systems, subsequently forming a dislocation slip band. The modified creep–fatigue life prediction model, incorporating strain energy dissipation and stress relaxation mechanisms, demonstrates an accurate fatigue life prediction under creep–fatigue coupling, with a prediction accuracy within an error band of 1.86 times.
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spelling doaj-art-84e3fdc55357417f9688d36fdc6a44ca2025-08-20T02:33:38ZengMDPI AGCrystals2073-43522025-04-0115542910.3390/cryst15050429Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life AssessmentAnping Long0Xiaoshan Liu1Lei Xiao2Gaoxiang Zhang3Jiangying Xiong4Ganjiang Feng5Jianzheng Guo6Rutie Liu7State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaWedge Central South Research Institute Co., Ltd., Shenzhen 518045, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaState Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, ChinaAero-engine turbine vanes made from directionally solidified nickel-based superalloys often fail with crack formation from the external wall of cooling channels. Therefore, this study simulates the compressive load on the external wall of the vane and conducts a sequence of creep–fatigue evaluations at 980 °C to investigate the creep–fatigue damage mechanisms of a directionally solidified superalloy and to assess its life. It is found that at low strain ranges, creep damage is dominant, with creep cavities forming inside the specimen and fatigue sources mostly distributed in the specimen interior. As the strain range increases, the damage mechanism transitions from creep-dominated to creep–fatigue coupled damage, with cracks nucleating preferentially on the surface and exhibiting a characteristic of multiple fatigue sources. In the longitudinal (L) specimen, dislocations in multiple orientations of the {111}<110> slip system are activated simultaneously, interacting within the γ channels to form dislocation networks, and dislocations shear through the γ′ phase via antiphase boundary (APB) pairs. In the transverse (T) specimen, stacking intrinsic stacking faults (SISFs) accumulate within the limited {111}<112> slip systems, subsequently forming a dislocation slip band. The modified creep–fatigue life prediction model, incorporating strain energy dissipation and stress relaxation mechanisms, demonstrates an accurate fatigue life prediction under creep–fatigue coupling, with a prediction accuracy within an error band of 1.86 times.https://www.mdpi.com/2073-4352/15/5/429anisotropycreep–fatiguedirectionally solidified Ni-based superalloydamage mechanismlife assessment
spellingShingle Anping Long
Xiaoshan Liu
Lei Xiao
Gaoxiang Zhang
Jiangying Xiong
Ganjiang Feng
Jianzheng Guo
Rutie Liu
Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment
Crystals
anisotropy
creep–fatigue
directionally solidified Ni-based superalloy
damage mechanism
life assessment
title Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment
title_full Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment
title_fullStr Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment
title_full_unstemmed Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment
title_short Anisotropy in the Creep–Fatigue Behaviors of a Directionally Solidified Ni-Based Superalloy: Damage Mechanisms and Life Assessment
title_sort anisotropy in the creep fatigue behaviors of a directionally solidified ni based superalloy damage mechanisms and life assessment
topic anisotropy
creep–fatigue
directionally solidified Ni-based superalloy
damage mechanism
life assessment
url https://www.mdpi.com/2073-4352/15/5/429
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