The effect of orientation and sense of applied uniaxial stress on the morphology of coherent gamma prime precipitates in stress annealed nickel-base superalloy crystals

Tien, J. K.; Copley, S. M.

doi:10.1007/bf02663347

Cited by 153 publications

(34 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…These results indicate that, in the case of YH61, the elastic misfit of {100} planes parallel to the stress axis could not be fully relaxed by the compressive strain due to its higher positive lattice misfit (about 0.3% at room temperature [5]); therefore, {100} planes parallel to the stress axis were required to coalesce. On the other hand, in the case of Udimet 700, the elastic misfit of {100} planes parallel to the stress axis could be relaxed by the compressive strain due to its lower positive lattice misfit (0.02% at room temperature [13]); therefore, {100} planes parallel to the stress axis did not need to coalesce. Although more extensive discussion should be required to reveal the correct mechanism which causes the difference of the developed microstructures between YH61 and Udimet 700, the difference of the lattice misfit between both two alloys can be considered as one of possible causes of the difference as discussed above.…”

Section: ) (Mmmentioning

confidence: 99%

A Study on Bending Deformation Behavior of NI-Based DS and SC Superalloys

Tamaki¹,

Fujita²,

Okayama³

et al. 2004

Superalloys 2004 (Tenth International Symposium)

View full text Add to dashboard Cite

IntroductionBending deformation behavior of Ni-based directionally solidified (DS) and single crystal (SC) superalloys was studied. For a DS superalloy, bending creep curves at 800, 850 and 900 O C were obtained. As a result, the stress exponents for the steady-state creep displacement rates of the bending creep were found to show the almost same values as those for the steady-state creep strain rates of the tensile creep. It was also confirmed that activation energy for the bending creep corresponded to that for the tensile creep within the temperature range of this study. It can be concluded from these results that the bending creep behavior of DS superalloys can be deduced from the simple tensile creep test data because the correspondence of the deformation mechanism between the bending and the tensile creep was proven.Uniaxial tensile deformations such as creep have been extensively characterized for Ni-based directionally solidified (DS) and single crystal (SC) superalloys. However, only few studies [1] [2] have been reported concerning bending deformation behavior of Nibased DS and SC superalloys. It can be considered as very important to characterize bending deformation behavior of Nibased superalloys used for gas turbine components because bending stresses are often observed in some critical portions of gas turbine blades and vanes. The representative example is the tip shroud [3]. The longer blades tend to be equipped with the tip shroud in order to effectively reduce gas leakage and increase high cycle fatigue margin on fundamental modes such as 1 st bending. The overhanging of the shroud causes a relatively high bending stress at the fillet which has become to be exposed to more severe circumstances due to the increase in gas-firing temperature of modern gas turbines. For reasons mentioned above, precise investigations of bending deformation behavior of Ni-based DS and SC superalloys have been required.For a SC superalloy, notable secondary orientation dependence of the steady-state creep displacement rates was observed at 750 O C/950MPa. The specimen, whose slip system caused the 45 Oshear-type slip, exhibited apparently faster creep displacement rate than the specimen, whose slip system caused the hinge-type deformation, even if their tensile/compressive directions were same. At 982 O C/294MPa, secondary orientation dependence of the creep displacement rates was not significant while [011] specimens showed higher creep resistance than [001] specimens. The microstructural observations after bending creep tests provided interesting results that one type of raft-like microstructure observed in the tension side of [011] specimens was also found in the compression side of [001] specimens and another type of raft-like microstructure observed in the compression side of the [011] specimens was also found in the tension side of the [001] specimens.

show abstract

Section: ) (Mmmentioning

confidence: 99%

A Study on Bending Deformation Behavior of NI-Based DS and SC Superalloys

Tamaki¹,

Fujita²,

Okayama³

et al. 2004

Superalloys 2004 (Tenth International Symposium)

View full text Add to dashboard Cite

show abstract

“…The driving force for migration of solute elements is discussed in the light of local stress field calculations using finite element modelling. Oriented coarsening has been observed for more than thirty years in both polycrystal and single crystal two-phase materials [1][2][3][4][5]. This [5][6][7].…”

mentioning

confidence: 99%

“…Oriented coarsening has been observed for more than thirty years in both polycrystal and single crystal two-phase materials [1][2][3][4][5]. This [5][6][7]. Clearly, the driving force for oriented coarsening is a combination of coherency misfit internal stresses and applied stress.…”

mentioning

confidence: 99%

Concentration Gradients near Heterophase Boundaries in Crept Single Crystal Nickel Base Superalloys

Blavette

Letellier

Racine

et al. 1996

Microsc. Microanal. Microstruct.

View full text Add to dashboard Cite

show abstract

“…1,8 Most Gamma prime in nickel-austenite has a lattice constant (a) very nearly the same as austenite (γ); for example in Udimet-700 the γ' lattice is only 0.02% greater than that of the γ matrix. 18 Thus the precipitate particles invariably occur as coherent or nearly coherent with the matrix. 1,8 TEM studies of the morphology and coherency of γ' in Astroloy were conducted by Macia and Sanders.…”

Section: Gamma Prime (γ')mentioning

confidence: 99%

“…8 Similarly additions of refractory elements with slow diffusion rates and high melting points like molybdenum and tungsten will significantly retard the rate of γ ΄ ripening. 1 Overall the approach to forestall ripening is two fold: (1) increase the volume percent of γ ΄ and (2) 18 The important concept of how the γ ΄ precipitates interact with dislocation movement responsible for observed properties of flow will be differed until after dislocations are discussed.…”

Section: Gamma Prime (γ')mentioning

confidence: 99%

Superalloy Metallurgy a Gleeble Study of Environmental Fracture in Inconel 601

Demmons¹

View full text Add to dashboard Cite

Superalloy Metallurgy a Gleeble Study of Environmental Fracture in Inconel 601Alan Demmons At temperatures above 0.5 Tm and in aggressive atmospheres predicting alloy performance is particularly challenging. Nickel alloys used in regimes where microstructure and properties are altered dynamically present unique requirements. Exposure may alter properties with unexpected early failure. The Gleeble is a valuable tool for investigation and simulation of thermo-mechanical properties of an alloy in various regimes up to the threshold of melting. In this study, four regimes of temperature and strain rate were simulated in an argon atmosphere to both investigate and document normal and abnormal failure modes. Commercial Inconel 601 was tested in selected regimes and in two treatments (as received and strain aged). Next two exposed conditions (TEOS and Hydride) were tested. Slow strain-rate and high temperature produced brittle intergranular fracture. Exposure at elevated temperature to process gases reduced both strength and ductility in both TEOS and Hydride. TEOS exposure reduced reduction in area in the alloy significantly more than the Hydride exposure.

show abstract

The effect of orientation and sense of applied uniaxial stress on the morphology of coherent gamma prime precipitates in stress annealed nickel-base superalloy crystals

Cited by 153 publications

References 12 publications

A Study on Bending Deformation Behavior of NI-Based DS and SC Superalloys

A Study on Bending Deformation Behavior of NI-Based DS and SC Superalloys

Concentration Gradients near Heterophase Boundaries in Crept Single Crystal Nickel Base Superalloys

Superalloy Metallurgy a Gleeble Study of Environmental Fracture in Inconel 601

Contact Info

Product

Resources

About