Competing Modes for Crack Initiation from Non-metallic Inclusions and Intrinsic Microstructural Features During Fatigue in a Polycrystalline Nickel-Based Superalloy

Stinville, J.C.; Martin, Étienne; Karadge, M.; Ismonov, Shak; Soare, Monica; Hanlon, Tim; Sundaram, Sairam; Echlin, McLean P.; Callahan, Patrick G.; Lenthe, William C.; Miao, Jr‐Ming; Wessman, Andrew; Finlay, Rebecca; Loghin, Adrian; Marte, J.S.; Pollock, Tresa M.

doi:10.1007/s11661-018-4780-3

Cited by 39 publications

(5 citation statements)

References 15 publications

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“…In parallel, annealing twin boundaries (TB) were also found as potential crack initiation sites in nickel base superalloys, including Alloy 718, due to intense strain localization that develops near and parallel to them [6,[10][11][12][13][14][15]. Slip activity at TB was attributed to the high elastic anisotropy of nickel base superalloys ("typical" Zener anisotropy ratio of 2.0 for 718 measured by Haldipur [16]) that promotes easy dislocation glide near and parallel to the {111} R3 twin boundary plane.…”

Section: Introductionmentioning

confidence: 99%

Role of Non-metallic Inclusions and Twins on the Variability in Fatigue Life in Alloy 718 Nickel Base Superalloy

Texier

Stinville

Charpagne

et al. 2020

The Minerals, Metals &Amp; Materials Series

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Non-metallic inclusions (NMIs) and slip bands parallel to and slightly offset from twin boundaries are observed to be preferential sites for fatigue crack nucleation in wrought superalloys. Potential interactions between NMI cracking and slip activity within neighboring grains or at twin boundaries were investigated under monotonic tensile loading (up to 1.3% total strain) at room temperature. High resolution-and Heaviside-digital image correlation measurements were performed during interrupted tensile loading to identify strain localization, associated slip systems, and damage initiation. Different mechanisms and scenarios were identified: (1) Microplasticity generally starts at twin boundaries even at stresses as low as 70% of the macroscopic yield strength, (2) transgranular slip activity intensively develops above the macroscopic yield stress, (3) intense slip activity develops near and parallel to 21% of the twin boundaries intercepting NMIs, (4) 7% of the twin boundaries intercepting NMIs lead to slip-assisted NMI cracking, (5) no transgranular slip activity participates in NMI cracking, (6) the fraction of cracked NMIs progressively increases with the load, and (7) within the NMIs that initiated cracks, 67% cracked below 90% of the macroscopic yield strength without the presence of slip activity in the neighboring grains. While slip-assisted NMI cracking was evidenced in the present study, most NMI cracking is due to strain incompatibility between NMIs and neighboring grains at the high end of the elastic regime without slip interaction.

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Section: Introductionmentioning

confidence: 99%

Role of Non-metallic Inclusions and Twins on the Variability in Fatigue Life in Alloy 718 Nickel Base Superalloy

Texier

Stinville

Charpagne

et al. 2020

The Minerals, Metals &Amp; Materials Series

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“…Compared with the microstructure of the as‐built specimen, it can be found that the number of strengthening phases increases significantly with the longer elevated temperature exposure time. On the other hand, research shows that the oxide film coving on the specimen surface could induce crack closure of surface small cracks 40 . Thus, SLM GH4169 could maintain elevated temperature fatigue resistance.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, research shows that the oxide film coving on the specimen surface could induce crack closure of surface small cracks. 40 Thus, SLM GH4169 could maintain elevated temperature fatigue resistance.…”

Section: Fatigue Tests and Fractographymentioning

confidence: 99%

Interior long‐life‐fatigue cracking behavior and life prediction of a selective laser melted GH4169 superalloy at different temperatures and stress ratios

Sun

Zhang

et al. 2022

Fatigue Fract Eng Mat Struct

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The axial fatigue tests at elevated (650 C) temperature with stress ratios of 0.1 and À1 were conducted under the loading cycle range of 10 4 -10 8 cycles to investigate interior cracking mechanism at elevated temperature of one selective laser melted GH4169 superalloy. Results showed that the interior fatigue crack nucleation was the main failure mode with both stress ratios at 650 C in the long-life regime. The interior crack nucleation region consisting of many facets was formed under shear stress and strain according to the 3D morphology restructure of the fracture surface. Combined with the evaluation of the threshold stress intensity factor, the transition lengths from a small crack to a long crack for interior failure at both stress ratios were evaluated. Based on the above analysis, the microstructure-related interior failure mechanism was summarized. Finally, crack nucleation and propagation lives were predicted to obtain the total fatigue life, which showed that the prediction and experimental data scattered between the factor-of-three boundaries.

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“…The impact of inclusions on superalloys varies significantly under different conditions. Factors such as temperature, loading method, size, and location all influence the failures induced by inclusions [8][9][10]. Hou et al [8] studied the fracture mechanism of nickel-based superalloy K4750 under high cycle fatigue and found that the cracks originated from large-size inclusions.…”

Section: Introductionmentioning

confidence: 99%

Effect of Pre-Added HfO2 Inclusions on Carbide Morphology and Deformation Behavior in DZ125 Nickel-Based Superalloy

Feng,

Liu,

Wang

et al. 2024

Metals

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Inclusions are important phases affecting material properties in complicated ways. In this paper, a quantitative study of the addition of HfO2 inclusions to DZ125 nickel-based superalloys was performed. Experimental results showed that the introduction of HfO2 inclusions caused a loss of strength and ductility. The carbide morphology also changed significantly from skeletal-shaped to block-shaped, resulting in a remarkable discrepancy in the fracture behavior under quasi-in-situ tensile testing. The SEM dynamic observations showed that cracks were initiated from the skeletal carbides and almost failed to propagate into the matrix. In contrast, the damage behavior of block-shaped carbides also involved internal cracking but with a tendency to form interconnected microcracks during propagation. A crystal plasticity finite element model (CPFEM) method was further developed to study the stress/strain behavior during the deformation process, considering the crystal orientations and microstructure morphologies from the EBSD data. Those elastoplastic parameters were determined through nanoindentation experiments. Simulation results verified that blocky carbides produced a pronounced strain concentration at the interface of the carbides and matrix, thereby increasing the tendency of crack formation. This paper provides a fundamental understanding of the role of inclusions in material recycling applications.

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Competing Modes for Crack Initiation from Non-metallic Inclusions and Intrinsic Microstructural Features During Fatigue in a Polycrystalline Nickel-Based Superalloy

Cited by 39 publications

References 15 publications

Role of Non-metallic Inclusions and Twins on the Variability in Fatigue Life in Alloy 718 Nickel Base Superalloy

Role of Non-metallic Inclusions and Twins on the Variability in Fatigue Life in Alloy 718 Nickel Base Superalloy

Interior long‐life‐fatigue cracking behavior and life prediction of a selective laser melted GH4169 superalloy at different temperatures and stress ratios

Effect of Pre-Added HfO2 Inclusions on Carbide Morphology and Deformation Behavior in DZ125 Nickel-Based Superalloy

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