Improvement of Creep strength in a nickel-base single-crystal superalloy by heat treatment

Caron, Pierre; Khan, T.

doi:10.1016/0025-5416(83)90199-4

Cited by 365 publications

(104 citation statements)

References 4 publications

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“…In an ideal situation, with y'-rafts extending from one side of the crystal to the other in an almost perfectly regular manner, gliding/climbing around it by matrix dislocations is impossible. This conclusion is in accordance with opinions of other authors [ 1,13,21,23,24]. Another example for enhanced creep properties due to tensile pre-rafting can be found in [25].…”

Section: Introductionsupporting

confidence: 91%

Enhancement of the High-Temperature Tensile Creep Strength of Monocrystalline Nickel-Base Superalloys by Pre-rafting in Compression

Tetzlaff¹,

Mughrabi²

2000

Superalloys 2000 (Ninth International Symposium)

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In recent years, the development of Y.-hardened monocrystalline nickel-base superalloys focused on different aspects of alloy composition and microstructural refinement. In particular, the formation of so-called y/y'-raft structures, lying typically, in the case of a negative y/y'-lattice misfit 6, perpendicular to the stress axis during high-temperature tensile creep had attracted much attention. Unfortunately, this microstructural transformation leads in most cases to deteriorated creep properties. Earlier attempts to prevent rafting by suitable prior annealing treatments had been in so far unsuccessful, that while the applied annealing treatment retarded raft formation, it inevitably lead to microstructural coarsening accompanied by creep acceleration. The goal of the present extensive study is to show that suitable pre-rafting in compression, leading to a y/y'-raft structure parallel to the stress axis in the case of a negative lattice misfit, enhances not only the isothermal hightemperature fatigue strength, as shown earlier, but also the hightemperature creep properties. The observed macroscopic creep behaviour will be discussed with reference of microstructural observations.

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Section: Introductionsupporting

confidence: 91%

Enhancement of the High-Temperature Tensile Creep Strength of Monocrystalline Nickel-Base Superalloys by Pre-rafting in Compression

Tetzlaff¹,

Mughrabi²

2000

Superalloys 2000 (Ninth International Symposium)

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“…At intermediate and high temperature the deformation is controlled by dislocation activity and by the rafting phenomenon. At 1223 K (950 ℃) microstructure S is stronger because the longer ageing time gives it a more ordered structure [9]. The F material despite having a smaller precipitate size, which should imply a smaller γ channel width, is much more irregular so that regions of thick γ are more common.…”

Section: Discussionmentioning

confidence: 99%

Computational Fluid Dynamics Modelling of Heat Treatment of Single Crystal Nickel Based Superalloys for Turbine Blade Application

Cosentino¹,

Warnken²,

Gebelin³

et al. 2012

Superalloys 2012 (Twelfth International Symposium)

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A numerical model based on computational fluid dynamics (CFD) is developed to simulate the vacuum heat treatment of single crystal turbine blades. Radiation and forced convection heat transfer are taken into account to model ramping-up, holding and gas fan quenching. This enables quantitative predictions to be made of temperature fields inside a laboratoryscale vacuum furnace. The uniformity of the expected temperature field is studied with a particular aim to predict hot spots or locations with higher risk of incipient melting. Simulation of the gas fan quenching process allows estimation of the quench rate to be made as a function of position within the furnace and critical furnace processing parameters. The effect of quench rate and ageing time on the microstructure of RR3010 superalloy has been characterised using scanning electron microscopy. Two representative structures with different average γ size have been tested in creep in three temperature regimes and with three different level of stresses, in an attempt to gain better understanding of the influence of microstructure on creep performance. Our results indicate that at lower creep testing temperatures, larger γ size confers longer time to rupture; however, as the testing temperature increases, the influence of microstructure is less pronounced.

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“…The primary slip plane was identified using Laue X-ray imaging and the test-piece sectioned vertically, parallel to the tensile axis. For high resolution imaging the primary slip plane (-111) was perpendicular to the foil normal [110] and the Burgers vector of the highest Schmid Factor [1][2][3][4][5][6][7][8][9][10][11][12](-111) slip system lies in the plane of the foil. Hence an edge dislocation in this system a/3 [1][2][3][4][5][6][7][8][9][10][11][12] has its line vector parallel to the foil normal and would be in the ideal configuration to image the atom alignment at high resolution.…”

Section: Methodsmentioning

confidence: 99%

“…For high resolution imaging the primary slip plane (-111) was perpendicular to the foil normal [110] and the Burgers vector of the highest Schmid Factor [1][2][3][4][5][6][7][8][9][10][11][12](-111) slip system lies in the plane of the foil. Hence an edge dislocation in this system a/3 [1][2][3][4][5][6][7][8][9][10][11][12] has its line vector parallel to the foil normal and would be in the ideal configuration to image the atom alignment at high resolution. The sample was also cut on the other vertical section normal to [1][2][3][4][5][6][7][8][9][10] and horizontally normal to [001] for imaging the dislocations and stacking faults at lower magnification.…”

Section: Methodsmentioning

confidence: 99%

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Dislocations in a Ni-based superalloy during low temperature creep

Rae

Vorontsov

Kovařík

et al. 2014

MATEC Web of Conferences

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Abstract.The nature and variety of the dislocations passing through the two-phase γ γ microstructure of Ni-based superalloys is key to the properties of these materials. The chemistry, size and arrangement of the precipitates greatly affects the nature of these dislocations. We present High Angle Annular Dark Field (HAADF) TEM observations of the structure of dislocations entering, passing through the γ precipitates in the singlecrystal superalloy CMSX-4 R . The creep deformation of the sample was interrupted after 8 hours at 750 • C and 750 MPa, a critical stage just as secondary creep was being established, and shows a range of defects in both phases, not always those predicted by the Schmid factor for the deformation geometry. We show that dislocations lodged in the γ γ interfaces have a significant effect on the structure of the interface and that they combine to produce stacking faults which cut through the γ . The implications of these observations for secondary creep deformation are discussed.CMSX-4 R is a registered Trade Mark of the Cannon Muskegon Company.

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Improvement of Creep strength in a nickel-base single-crystal superalloy by heat treatment

Cited by 365 publications

References 4 publications

Enhancement of the High-Temperature Tensile Creep Strength of Monocrystalline Nickel-Base Superalloys by Pre-rafting in Compression

Enhancement of the High-Temperature Tensile Creep Strength of Monocrystalline Nickel-Base Superalloys by Pre-rafting in Compression

Computational Fluid Dynamics Modelling of Heat Treatment of Single Crystal Nickel Based Superalloys for Turbine Blade Application

Dislocations in a Ni-based superalloy during low temperature creep

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