Article
Engineering, Mechanical
Qinan Han, Wei Wang, Jianwen Fang, Haitao Cui, Hongjian Zhang, Xiaolin Yang, Qinqin Mu, Jian Xu, Huiji Shi
Summary: This work conducted in-situ scanning electron microscope (SEM) fretting fatigue experiments using dovetail shape specimens to study the failure of the turbine blade-disc dovetail joint in aero-engines. The study captured the fretting fatigue damage process and quantified the misorientation and geometrically necessary dislocation (GND) density induced by fretting fatigue.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
R. Branco, P. A. Prates, J. D. Costa, J. A. Martins Ferreira, C. Capela, F. Berto
Summary: This study examines the notch fatigue behavior and crack initiation life estimation in maraging steel fabricated by laser beam powder bed fusion under multiaxial loading through experiments and numerical simulations. The results show that both simulation methods accurately predict the crack initiation sites, directions of crack growth, and fatigue life, with elastic-plastic predictions leading to smaller errors but slightly shifting to the non-conservative side.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Shanlin Li, Qu Liu, Shao-Shi Rui, Xiaogang Li, Mengjia Hu, Kejian Li, Qixing Sun, Zhipeng Cai, Jiluan Pan
Summary: In this study, fatigue crack initiation behaviors around defects induced by welding thermal cycle in IN617B were investigated. Two mechanisms of fatigue crack initiation were clarified, and the dominant mechanism was determined by the distance of crack initiation from defects. Welding defects altered the deformation mode of the near-field region, accelerating the fatigue failure process.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Z. Liang, A. Liu, X. S. Wang, N. Q. Zhang
Summary: This study investigated the small fatigue crack initiation and propagation behavior of Inconel 617 using various methods, and quantitatively measured the local micro-scale strain field of the material with a new technique. A simulation model was established and a new framework was constructed for predicting crack path and lifetime.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
W. T. Zhang, R. Jiang, Y. Zhao, L. C. Zhang, L. Zhang, L. G. Zhao, Y. D. Song
Summary: The macro and mesoscale deformation and damage of the PM nickel-based superalloy FGH4098 under low cycle fatigue loading at elevated temperatures were investigated. The results indicate that higher temperature leads to more severe macroscale damage and shorter fatigue life. The distribution and evolution of fatigue damage are strongly affected by local stress-strain state and temperatures.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
J. Telesman, T. P. Gabb, P. T. Kantzos, P. J. Bonacuse, R. L. Barrie, C. A. Kantzos
Summary: In this study, crack initiation, crack coalescence, and small crack growth behavior of over 400 seeded inclusions in P/M Udimet 720 nickel disk alloy were monitored during interrupted low cycle fatigue testing at 650 degrees C. Two types of seeded alumina inclusions were used with average sizes of 54 μm and 122 μm, with fatigue behavior sub-categorized into four groups and detailed visual maps developed for inclusion size/cycle history. The effect of surface residual stresses on fatigue life was also investigated.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Nanoscience & Nanotechnology
T. Babinsky, I Kubena, I Sulak, T. Kruml, J. Tobias, J. Polak
Summary: The study focused on the surface relief evolution and fatigue crack initiation of Rene'41 superalloy, revealing the crucial role of persistent slip markings in fatigue crack initiation at room temperature.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Yujie Zhang, Cheng Hou, Xiaochao Jin, Dongxu Li, Litao Zhao, Laixia Yang, Xueling Fan
Summary: In this paper, the thermal fatigue crack initiation and propagation behaviors of GH3230 nickel-based superalloy were studied under different peak temperatures. The results show that the increase of peak temperature leads to a decrease in thermal fatigue crack initiation life, faster crack propagation, and easier accumulation of thermal deformation.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Nanoscience & Nanotechnology
Xiaoyi Ren, Junxia Lu, Jianli Zhou, Xianqiang Liu, Wenxiang Jiang, Jin Wang, Yuefei Zhang, Ze Zhang
Summary: This study investigated the relationship between fatigue behavior and microstructural evolution of a second-generation nickel-based single-crystal superalloy. The results showed that deformation and fatigue crack propagation varied with different crystal orientations, and fatigue life was influenced by the elastic modulus.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
C. H. Wu, R. Jiang, L. C. Zhang, Y. C. Wang, Y. Chen, Y. D. Song
Summary: This study investigates the fatigue crack growth (FCG) mechanisms of Ni-based superalloy FGH4098 at temperatures ranging from 650 to 800 degrees Celsius. The results show that the FCG rate increases by 2-3 orders of magnitude with increased temperature and prolonged dwell time, which is attributed to grain boundary oxidation. Characterization of the crack tips reveals that deformation, such as dislocations and stacking faults, mainly occurs within the gamma channel, accompanied by a change in grain orientation due to severe deformation. Pre-formed oxides at uncracked grain boundaries facilitate the FCG process. A mechanism map of the interaction between deformation-assisted grain boundary oxidation and FCG is proposed.
Article
Materials Science, Multidisciplinary
Donghyuk Kim, Rong Jiang, Ian Sinclair, Philippa Reed
Summary: The effects of unimodal secondary gamma' size and grain orientation on fatigue crack initiation and early crack propagation at room temperature were investigated in RR1000 alloy. The results showed that cracks mainly initiated at slip bands and/or pores followed by crystallographic facet formation. More diffuse strain localisation around the pores was observed by SEM-DIC analysis. Fatigue lifetime was found to be linked to the number of crack initiations and consequent crack coalescence, which accelerated crack propagation. Slip trace analysis with EBSD mapping indicated that cracks are likely to propagate along the primary active slip system with a relatively high Schmid Factor. In the conducted tests, the stochasticity of crack initiation events had a greater impact on overall lifetime than variations in secondary gamma' size.
MATERIALS SCIENCE AND TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Pengfei Wang, Xinbao Zhao, Quanzhao Yue, Wanshun Xia, Qingqing Ding, Hongbin Bei, Yuefeng Gu, Ze Zhang
Summary: The oxidation-assisted initiation of surface cracks in a fourth-generation Ni-based single crystal superalloy during low cycle fatigue at 900 degrees C and 980 degrees C was systematically investigated. The results showed that at 900 degrees C, cracks initiated near surface defects, while at 980 degrees C, cracks initiated in the surface oxide layer. In addition, microcracks in the outer oxide layer quickly connected with microcracks at the surface and inner/outer oxide layer interface at 980 degrees C. These cracks eventually became channels for rapid oxygen transport, accelerating the crack growth rate.
Article
Metallurgy & Metallurgical Engineering
Guo Haohan, Yang Jie, Liu Fang, Lu Rongsheng
Summary: Nickel-based GH4169 superalloy is commonly used in aeroengines due to its favorable properties. The study focuses on the fatigue behavior and fatigue life of GH4169 superalloy to ensure the safety and reliability of aeroengines. Constraint is an important factor affecting the fatigue fracture behavior of materials. The study introduces two fatigue indicators and investigates the relationship between constraint and fatigue crack initiation life, providing insights into the effect of constraint on fatigue crack initiation time.
ACTA METALLURGICA SINICA
(2022)
Article
Computer Science, Interdisciplinary Applications
Rupesh Kumar D. Verma, Giang D. Nguyen, Murat Karakus, Abbas H. Taheri, Ha H. Bui
Summary: This paper presents a combined numerical-experimental approach to investigate crack initiation and development in brittle rocks. The proposed approach demonstrates the potential for capturing rock responses at both scales through numerical simulation and experimental validation.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Engineering, Mechanical
Shengming Wen, Zhicheng Liu, Dong Mi, Bochuan Li, Sihui Yang, Chao Jiang
Summary: This study investigates the fatigue crack propagation mechanism of electron beam welded joints of GH4169 Ni-based superalloy through in-situ scanning electron microscope (SEM) experiments. It is found that the welded joint has comparable static strength but worse plasticity compared to the base material. Interestingly, the welded joint exhibits a longer fatigue crack growth life than the base material. The fatigue crack growth rate (FCGR) curves of the welded joint and the base material intersected with each other, with the FCGR of the welded joint being lower at low stress intensity factors and higher at high stress intensity factors.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Lu Zhang, Liguo Zhao, Rong Jiang, Chris Bullough
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2020)
Article
Nanoscience & Nanotechnology
Y. G. Tan, D. J. Bull, R. Jiang, A. Evangelou, S. Chaudhuri, S. Octaviani, F. Pierron, N. Gao, H. Toda, I Sinclair, P. A. S. Reed
Summary: The crack initiation and early propagation behavior of DS superalloy CM247LC was assessed using various imaging techniques. Three modes of secondary crack behaviors were identified, with early fatigue damage controlled by microstructure-induced cracking, mainly carbide cracking. The mechanisms of these cracking behaviors are associated with the plastic zone of the main crack tip, with carbide-induced cracking more likely to occur in the early stages of the fatigue process.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
R. Jiang, L. C. Zhang, Y. Zhao, X. H. Chen, B. Gan, X. C. Hao, Y. D. Song
Summary: The study found that GH4169 alloy undergoes oxidation and sulfidation during hot corrosion, forming a sulfide layer beneath the oxide layer. Hot corrosion accelerates fatigue crack initiation and significantly reduces the alloy's fatigue life.
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
(2021)
Article
Engineering, Mechanical
D. Kim, R. Jiang, A. Evangelou, I Sinclair, P. A. S. Reed
Summary: Two distinct unimodal gamma' size distributions were produced in a disc alloy to study the effects on fatigue crack growth mechanisms at elevated temperature. The fine gamma' variant showed better resistance to fatigue crack growth for both dwell times, while the coarse gamma' variant exhibited faster and more time dependent behavior. Additionally, the presence of a more continuous distribution of carbides on the grain boundary in the coarse gamma' variant may influence oxidation behavior and intergranular fracture behavior.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Nanoscience & Nanotechnology
R. Jiang, L. C. Zhang, W. T. Zhang, Y. Zhang, Y. Chen, J. T. Liu, Y. W. Zhang, Y. D. Song
Summary: The study reveals that the low cycle fatigue failure mode and stress relaxation behavior of FGH4098 change with increasing temperature and dwell time, mainly influenced by microstructure.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Xu Jia, Zi-wen Zhang, Chen Ling, Xu-ping Lu, Rong Jiang, Ying-Dong Song
Summary: This study conducted high-speed ballistic impact tests and fatigue tests on GH4169 alloy samples to investigate the effect of FOD depth on fatigue strength. It was found that as the FOD depth increases, the damage length, material losses, and stress concentration coefficient also increase, resulting in a reduction in fatigue strength. The study also showed that the Kitagawa-Takahashi diagram can be used as a basic model for the design of FOD tolerance.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Engineering, Mechanical
W. T. Zhang, R. Jiang, Y. Zhao, L. C. Zhang, L. Zhang, L. G. Zhao, Y. D. Song
Summary: The macro and mesoscale deformation and damage of the PM nickel-based superalloy FGH4098 under low cycle fatigue loading at elevated temperatures were investigated. The results indicate that higher temperature leads to more severe macroscale damage and shorter fatigue life. The distribution and evolution of fatigue damage are strongly affected by local stress-strain state and temperatures.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Multidisciplinary
Donghyuk Kim, Rong Jiang, Ian Sinclair, Philippa Reed
Summary: The effects of unimodal secondary gamma' size and grain orientation on fatigue crack initiation and early crack propagation at room temperature were investigated in RR1000 alloy. The results showed that cracks mainly initiated at slip bands and/or pores followed by crystallographic facet formation. More diffuse strain localisation around the pores was observed by SEM-DIC analysis. Fatigue lifetime was found to be linked to the number of crack initiations and consequent crack coalescence, which accelerated crack propagation. Slip trace analysis with EBSD mapping indicated that cracks are likely to propagate along the primary active slip system with a relatively high Schmid Factor. In the conducted tests, the stochasticity of crack initiation events had a greater impact on overall lifetime than variations in secondary gamma' size.
MATERIALS SCIENCE AND TECHNOLOGY
(2022)
Article
Mechanics
Xu Jia, Chen Ling, Ziwen Zhang, Rong Jiang, Yingdong Song
Summary: This study investigates the impact of different incident foreign object damage (FOD) depths on the high-cycle fatigue (HCF) performance of TC11 titanium alloy specimens. Results show that increasing damage depth leads to higher stress concentration factors, greater material losses, and decreased fatigue strength. The study provides useful insight for assessing the notchtype FOD degree of TC11 titanium alloy leading edge blades.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Nanoscience & Nanotechnology
Y. Zhao, R. Jiang, A. Harte, D. J. Bull, P. A. S. Reed
Summary: This study characterizes the strain localization under cyclic loading in an advanced powder metallurgy Ni-based superalloy at 450°C. The results show that strain mainly accumulates in slip/strain bands, and the strain saturates at 1000 cycles. The strain bands mainly consist of shear strain along the strain band and transverse strain normal to the strain band.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
L. C. Zhang, R. Jiang, Y. C. Wang, L. Zhang, J. T. Liu, Y. W. Zhang, Y. D. Song
Summary: This study investigates the short fatigue crack propagation behavior of a powder metallurgy superalloy (FGH4098) for aeroengine turbine disc application. The results show that the grain boundary oxidation has a significant influence on the crack propagation, and the temperature has a more evident effect on the fine-grained FGH4098 compared to the coarse-grained FGH4098.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
C. H. Wu, R. Jiang, L. C. Zhang, Y. C. Wang, Y. Chen, Y. D. Song
Summary: This study investigates the fatigue crack growth (FCG) mechanisms of Ni-based superalloy FGH4098 at temperatures ranging from 650 to 800 degrees Celsius. The results show that the FCG rate increases by 2-3 orders of magnitude with increased temperature and prolonged dwell time, which is attributed to grain boundary oxidation. Characterization of the crack tips reveals that deformation, such as dislocations and stacking faults, mainly occurs within the gamma channel, accompanied by a change in grain orientation due to severe deformation. Pre-formed oxides at uncracked grain boundaries facilitate the FCG process. A mechanism map of the interaction between deformation-assisted grain boundary oxidation and FCG is proposed.
Article
Materials Science, Multidisciplinary
D. Kim, R. Jiang, P. A. S. Reed
Summary: The effects of microstructure and oxidation on fatigue crack initiation and early propagation processes were investigated in RR1000 turbine disc alloy with different gamma' and carbide distributions. Fatigue tests were conducted at 650 degrees C in air using three-point bending and trapezoidal waveform loading. Intergranular features were clearly observed in both gamma' variants, with fatigue cracks initiating at grain boundaries containing Co-rich oxides and interfaces between carbides and grain boundaries due to oxidation damage under applied loading. Enhanced fatigue crack growth rates were attributed to significant intergranular crack initiation and frequent crack coalescence events, particularly where more continuous carbides exist at the grain boundary.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Engineering, Mechanical
R. Jiang, Y. C. Wang, L. C. Zhang, Y. Chen, H. Zhang, Z. B. Wang, Y. D. Song
Summary: Constant load amplitude, Delta K fatigue crack propagation (FCP) tests were conducted to investigate the FCP behavior of the grain size transition zone in a dual microstructure turbine disc. The results indicate that grain size has a more significant influence in the time-dependent FCP regime, but its effect is relatively limited in the cycle-dependent FCP regime. A larger local plastic deformation zone is observed in the fine-grained region, which is believed to be the cause of more significant grain boundary oxidation, resulting in accelerated FCP through the contribution of more grain boundaries acting as short-circuit diffusion paths of oxide-forming elements.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
