Primary creep in single crystal superalloys: Origins, mechanisms and effects

Rae, C.M.F.; Reed, Roger C.

doi:10.1016/j.actamat.2006.09.026

Cited by 278 publications

(167 citation statements)

References 16 publications

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“…The pairs themselves are, in turn, separated by narrow region of APB. This small separation agrees closely with TEM observations [2] in 2 nd generation superalloys. In the case of the model the close separation is explained by the fact that the CB dislocation experiences a greater resolved stress than the CA before it.…”

Section: Resultssupporting

confidence: 80%

“…Building on the work of Kear et al [15][16][17], Pollock and Argon [18] and TEM observations, Rae and Reed [2] suggest that primary creep at low temperatures (750-850 • C) and high stresses (≈750 MPa) in CMSX-4 proceeds first by the nucleation of sufficient a 2 110 dislocations. These combine into a 112 dislocation ribbons, via reactions like:…”

Section: Comparison With Experimental Observationsmentioning

confidence: 99%

“…Primary creep occurs in 2 nd generation superalloys at 750-850 • C when a threshold stress of ≈ 500MPa is exceeded [2]. This temperature-dependent threshold stress correlates directly to the ability of a 112 dislocation ribbons to nucleate in the γ matrix, then enter and shear γ precipitates.…”

Section: Introductionmentioning

confidence: 99%

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Shearing of γ′ precipitates by a〈112〉 dislocation ribbons in Ni-base superalloys: A phase field approach

et al. 2010

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The "phase field microelasticity theory of dislocations" has been used to study the propagation of dislocation ribbons with an overall Burgers vector of a 112 through a simulated Ni-base superalloy. The driving force for dislocation dissociation reactions and formation of planar faults is incorporated into the free energy using γ-surface functions specially fitted to ab initio data. The model shows that the mechanism of cutting of the γ precipitates by these ribbons exhibits significant dependence on stress magnitude, orientation and precipitate shape. In the case of mixed screw-edge ribbons a change of shearing mode is observed, from stacking fault shear to APB shear, when the applied stress approaches the yield of the material. This transition is absent in pure edge ribbons.

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Section: Resultssupporting

confidence: 80%

Section: Comparison With Experimental Observationsmentioning

confidence: 99%

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Shearing of γ′ precipitates by a〈112〉 dislocation ribbons in Ni-base superalloys: A phase field approach

et al. 2010

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“…The structure of these dislocations and their role in viscous slip of superalloys was originally discussed by Kear et al [4,5]. TEM studies [3,6] have shown that the a 2 112 dislocations making up the a 112 ribbon are dissociated into partial dislocations enclosing a low energy superlattice intrinsic or extrinsic stacking fault (SISF and SESF respectively). According to these studies, the dissociation of a complete a 112 ribbon in the γ would take place according to the following scheme: It should be noted, that the a 112 dislocation is rarely observed passing through a single γ precipitate in its entirety.…”

Section: Introductionmentioning

confidence: 99%

“…The main source of creep strain in this regime is the propagation of a 112 dislocation ribbons through both γ and γ phases [3]. The structure of these dislocations and their role in viscous slip of superalloys was originally discussed by Kear et al [4,5].…”

Section: Introductionmentioning

confidence: 99%

High-resolution electron microscopy of dislocation ribbons in a CMSX-4 superalloy single crystal

Vorontsov¹,

et al. 2012

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Nickel‐Based Superalloys for Blade Application: Production, Performance and Application

Tin

Pollock

2010

Encyclopedia of Aerospace Engineering

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The continuing drive for improvements in the performance, operating temperatures, and emissions in advanced aircraft engines has driven the development of nickel‐based superalloys for decades. Nickel base superalloys are an unusual class of metallic materials with an exceptional combination of high temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments. Their performance in severe combustion and chemical environments materials has led to their widespread use in aircraft and power generation turbines, rocket engines, nuclear power plant components, marine engines, and a variety of chemical processing operations. Intensive alloy and process development activities over the past few decades have resulted in single crystal Ni‐based superalloys that can tolerate average temperatures of 1050°C with occasional excursions (or local hot spots near airfoil tips) to temperatures as high as 1200°C which is ∼90% of the melting point of the material. The fundamental aspects of the composition and structure that result in these exceptional properties are briefly reviewed. Single crystal Ni‐superalloys that are utilized in gas turbine engines and the advanced manufacturing processes used for their production are outlined along with characteristic mechanical and physical properties.

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Primary creep in single crystal superalloys: Origins, mechanisms and effects

Cited by 278 publications

References 16 publications

Shearing of γ′ precipitates by a〈112〉 dislocation ribbons in Ni-base superalloys: A phase field approach

Shearing of γ′ precipitates by a〈112〉 dislocation ribbons in Ni-base superalloys: A phase field approach

High-resolution electron microscopy of dislocation ribbons in a CMSX-4 superalloy single crystal

Nickel‐Based Superalloys for Blade Application: Production, Performance and Application

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