On the origin of creep dislocations in a Ni-base, single-crystal superalloy: an ECCI, EBSD, and dislocation dynamics-based study

Ram, Farangis; Li, Zhuangming; Zaefferer, Stefan; Haghighat, Seyed Masood Hafez; Zhu, Zailing; Raabe, Dierk; Reed, Roger C.

doi:10.1016/j.actamat.2016.02.038

Cited by 68 publications

(36 citation statements)

References 52 publications

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“…In such a heavily deformed area shown in Figure 1a, the background matrix itself has a large contrast across geometrically necessary dislocations (GNDs; Kaczorowski & Gerberich, 1991), so it is hard to distinguish the dislocation lines clearly like the image shown in Figure 1d. Moreover, based on the crystal orientation analysis, EBSD is limited as only the GND density can be obtained, rather than total dislocation density (Ram et al, 2016;Gutierrez-Urrutia & Raabe, 2012). Through further annealing, the grain grew by the migration of HAGB but no migration of the LAGB occurred (shown in Figure 2b,c).…”

Section: Resultsmentioning

confidence: 99%

“…However, it is hard to achieve this condition with non‐single crystal materials because of the principle of formation of electron channeling patterns. It can be achievable if SEM has the ability to collect selected area channeling patterns (SACPs) as the rocking incident beam but most of the latest models no longer have the configuration to provide SACPs (Joy et al, ; Ram et al, ; Mansour et al, ). Therefore, it is necessary to use the orientation information obtained by the EBSD (Gutierrez‐Urrutia, Zaeffere, & Raabe, ; Gutierrez‐Urrutia, Zaeffere, & Raabe, ).…”

Section: Introductionmentioning

confidence: 99%

“…The latter, EBSD (Venables & Harland, 1973), is widely used in crystallographic research such as phase identification and distribution. Moreover, it can be used as a microstructural quantification tool for texture analysis (Huang & Humphreys, 2001), grain size distribution (Takayama et al, 2005), and specifically for strain analysis (Wright, Nowell, & Field, 2011;Ram et al, 2016). ECCI and EBSD are state-of-the-art techniques that are comparable to each other and are complementary (Primig et al, 2010;Oh et al, 2016).…”

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confidence: 99%

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Low angle boundary migration of shot‐peened pure nickel investigated by electron channeling contrast imaging and electron backscatter diffraction

Cha

Kim

et al. 2019

Microscopy Res & Technique

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Study on recrystallization of deformed metal is important for practical industrial applications. Most of studies about recrystallization behavior focused on the migration of the high‐angle grain boundaries, resulting in lack of information of the kinetics of the low angle grain boundary migration. In this study, we focused on the migration of the low angle grain boundaries during recrystallization process. Pure nickel deformed by shot peening which induced plastic deformation at the surface was investigated. The surface of the specimen was prepared by mechanical polishing using diamond slurry and colloidal silica down to 0.02 μm. Sequential heat treatment under a moderate annealing temperature facilitates to observe the migration of low angle grain boundaries. The threshold energy for low angle boundary migration during recrystallization as a function of misorientation angle was evaluated using scanning electron microscopy techniques. A combination of electron channeling contrast imaging and electron backscatter diffraction was used to measure the average dislocation density and a quantitative estimation of the stored energy near the boundary. It was observed that the migration of the low angle grain boundaries during recrystallization was strongly affected by both the stored energy of the deformed matrix and the misorientation angle of the boundary. Through the combination of electron channeling contrast imaging and electron backscatter diffraction, the threshold stored energy for the migration of the low angle grain boundaries was estimated as a function of the boundary misorientation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Low angle boundary migration of shot‐peened pure nickel investigated by electron channeling contrast imaging and electron backscatter diffraction

Cha

Kim

et al. 2019

Microscopy Res & Technique

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“…33 This inclusion was generated as a result of a different processing route, and so the microstructure and properties of this inclusion structure are different than those discussed, as observed in the explicit microstructure rendered for the CPFE study shown in Fig. 8a.…”

Section: Cpfe Model Of Polycrystal Containing Second-phase Particle Fmentioning

confidence: 95%

“…To address this problem, ECCI is a promising technique to be used as an alternative dislocation characterization method to determine the total dislocation density. 32,33 The initial dislocation density was low and homogeneously distributed through the microstructure, and the presence of residual stress gradients was low. 31 After two cycles, the GND density and residual stress gradient ''hot spot'' (red) maps are shown in Fig.…”

Section: Hr-ebsd Study Of Plasticity In Polycrystals Containing a Secmentioning

confidence: 99%

Toward Predictive Understanding of Fatigue Crack Nucleation in Ni-Based Superalloys

Jiang

Dunne

Britton

2017

JOM

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Predicting when and where materials fail is a holy grail for structural materials engineering. Development of a predictive capability in this domain will optimize the employment of existing materials, as well as rapidly enhance the uptake of new materials, especially in high-risk, high-value applications, such as aeroengines. In this article, we review and outline recent efforts within our research groups that focus on utilizing full-field measurement and calculation of micromechanical deformation in Ni-based superalloys. In paticular, we employ high spatial resolution digital image correlation (HR-DIC) to measure surface strains and a high-angular resolution electron backscatter diffraction technique (HR-EBSD) to measure elastic distortion, and we combine these with crystal plasticity finite element (CPFE) modeling. We target our studies within a system of samples that includes single, oligo, and polycrystals where the boundary conditions, microstructure, and loading configuration are precisely controlled. Coupling of experiment and simulation in this manner enables enhanced understanding of crystal plasticity, as demonstrated with case studies in deformation compatibility; spatial distributions of slip evolution; deformation patterning around microstructural defects; and ultimately development of predictive capability that probes the location of microstructurally sensitive fatigue cracks. We believe that these studies present a careful calibration and validation of our experimental and simulation-based approaches and pave the way toward new understanding of crack formation in engineering alloys.

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Modeling anisotropic mechanical properties and creep behavior of Ni($$\gamma$$)/Ni3Al($$\gamma'$$) single crystal superalloys at high temperatures

Eshlaghi

Khoei

2023

J Nanopart Res

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On the origin of creep dislocations in a Ni-base, single-crystal superalloy: an ECCI, EBSD, and dislocation dynamics-based study

Cited by 68 publications

References 52 publications

Low angle boundary migration of shot‐peened pure nickel investigated by electron channeling contrast imaging and electron backscatter diffraction

Low angle boundary migration of shot‐peened pure nickel investigated by electron channeling contrast imaging and electron backscatter diffraction

Toward Predictive Understanding of Fatigue Crack Nucleation in Ni-Based Superalloys

Modeling anisotropic mechanical properties and creep behavior of Ni($$\gamma$$)/Ni3Al($$\gamma'$$) single crystal superalloys at high temperatures

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