TEMin situstraining of the MC2 superalloy at room temperature

Benyoucef, Mustafa; Clément, N.; Coujou, A.

doi:10.1080/01418619508239952

Cited by 30 publications

(17 citation statements)

References 13 publications

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“…[9][10][11][12][13][14][15][16][17][18][19] Microstructural information on high temperature/low stress creep is less frequent. Here, we summarize microstructural results, which are important for high temperature and low stress creep of singlecrystal Ni-base superalloys.…”

Section: Introductionmentioning

confidence: 99%

Miniature Specimen Assessment of Creep of the Single-Crystal Superalloy LEK 94 in the 1000 °C Temperature Range

Mälzer

Hayes²,

Mack

et al. 2007

Metall Mater Trans A

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The creep behavior of the Ni-base superalloy LEK 94 in the 1000°C range has been investigated. Miniature tensile specimens were employed, which can be taken out of a thin walled blade or used when only limited amounts of material are available. We show that this miniature test technique yields reasonable creep data, including stress exponents n and apparent activation energies Q app . The n values are close to 5 and the Q app values are close to 500 kJ/mole, independent of the crystallographic direction. Creep rates are fastest for samples oriented in the [110] direction, followed by [001] samples. The lowest creep rates are observed for the [111] direction. This difference is related to a difference in resolved shear stresses and in the number of activated crystallographic slip systems. As a striking new result, it was observed that the onset of tertiary creep occurs earlier and rupture strains are significantly smaller in the case of [110] specimens as compared to [100] specimens, while the [111] specimens show an intermediate behavior. These effects are related to the alignment of cast porosity along the axis of primary dendrites. When cast micropores align perpendicular to the axis of the applied tensile stress, the onset of fast tertiary creep occurs early and small rupture strains are observed.

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Section: Introductionmentioning

confidence: 99%

Miniature Specimen Assessment of Creep of the Single-Crystal Superalloy LEK 94 in the 1000 °C Temperature Range

Mälzer

Hayes²,

Mack

et al. 2007

Metall Mater Trans A

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“…The image forces is comparable in magnitude with other forces acting on the dislocation and cannot be neglected, this force describes the behavior of the dislocations near an interface and explains observations of in situ TEM in several studies [11][12][13][14].…”

Section: Introductionmentioning

confidence: 76%

Elastic Interaction between Dislocation and Interface in Elastically Anisotropic Ceramic Bimaterials Al2O3-AlN: Image Force Effect

Aicha¹,

Omar²

2017

ujme

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The Al 2 O 3 and AlN materials are often used as electrical insulators (electronic substrates) also the case of pressure sensors where the aluminum nitride (AlN) is selected as the piezoelectric layer and the alumina (Al 2 O 3 ) as a solid substrate insulating. This study aims to investigate the mobility of dislocations near the heterophase interface of bimaterials based alumina (Al 2 O 3 ) under the effect of the image force, without the effect of temperature, deformation and external stress These dislocations having a Burgers vector b = 1/3 [112 � 0] , they are located in Al 2 O 3 . The interface is defined by its plane parallel to the dislocation line and disorientation varies between 0 and 180° around the axis [101 � 0]. Usually, the image force calculated in the context of the anisotropic linear elasticity using Barnett and Lothe theory with Stroh formalism, Fi = ∆E / d, where ∆E is the elastic interaction energy. The results show that dislocation motion under the image force effect depends on the elastic and crystallographic properties of the materials constituting the bicrystals and even disorientation of the interface which has an effect on the intensity of the elastic interaction energy. The dislocations are repelled to the interface if the difference in shear modulus between the two materials is positive (∆µ= µ 2 −µ 1 >0), they are attracted to the interface in the opposite case (∆µ= µ 2 −µ 1 <0).

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“…With this technique, the only one which allows direct observation of the evolution of the dislocation microstructure under stress and temperature, we have already identified such mechanisms in single-phased 0 -based monocrystals [1][2][3] as well as in single-phased monocrystals simulating the matrix of various industrial single crystal superalloys [4].…”

Section: Introductionmentioning

confidence: 96%

Decorrelated movements of Shockley partial dislocations in the γ-phase channels of nickel-based superalloys at intermediate temperature

Raujol

Benyoucef²,

Locq

et al. 2006

Philosophical Magazine

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In nickel-based superalloys with high volume fraction of 0 precipitates, dislocations have to experience high curvatures in order to enter narrow channels by glide in the {111} planes of the fcc matrix. Observations of in situ dynamic sequences performed in a transmission electron microscope on several industrial superalloys have shown the occurrence of decorrelated movements of Shockley partial dislocations, originating from perfect dislocation dissociation. By evaluating the effective stress acting on each one of these partial dislocations, as well as their respective flexibility, the possible occurrence of such movements for some particular dislocation characters and channel widths is accounted for. These movements can play an important role in the creep behaviour of these materials in the low deformation rate regime.

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TEMin situstraining of the MC2 superalloy at room temperature

Cited by 30 publications

References 13 publications

Miniature Specimen Assessment of Creep of the Single-Crystal Superalloy LEK 94 in the 1000 °C Temperature Range

Miniature Specimen Assessment of Creep of the Single-Crystal Superalloy LEK 94 in the 1000 °C Temperature Range

Elastic Interaction between Dislocation and Interface in Elastically Anisotropic Ceramic Bimaterials Al<sub>2</sub>O<sub>3</sub>-AlN: Image Force Effect

Decorrelated movements of Shockley partial dislocations in the γ-phase channels of nickel-based superalloys at intermediate temperature

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