Journal ArticleDOI
Rafting in single crystal nickel-base superalloys - An overview
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TLDR
In this article, the effect of stress state on γ/γ′ rafting, kinetics and morphological evolution are discussed with the recent experimental results, and the nature and influence of rafting on creep properties including pre-rafted conditions are discussed.Abstract:
Currently nickel-base single crystal (SX) superalloys are considered for the manufacture of critical components such as turbine blades, vanes etc., for aircraft engines as well as land-based power generation applications. Microstructure and high temperature mechanical properties are the major factors controlling the performance of SX superalloys. Rafting is an important phenomenon in these alloys which occurs during high temperature creep. It is essential to understand the rafting mechanism, and its characteristics on high temperature properties before considering the advanced applications. In this review article, the thermodynamic driving force for rafting with and without stress is explained. The nature and influence of rafting on creep properties including pre-rafted conditions are discussed. In addition, the effect of stress state on γ/γ′ rafting, kinetics and morphological evolution are discussed with the recent experimental results.read more
Citations
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Damage accumulation during creep deformation of a single crystal superalloy at 1150 °C
TL;DR: In this article, microstructural degradation in the CMSX-4 single crystal superalloy during creep deformation at 1150°C and 100MPa is studied. And it is shown that the high strain rates and shear stresses associated with the rupture process are sufficient to cause realignment of the rafted γ′ structure with respect to the γ matrix.
Journal ArticleDOI
Coupling between Re segregation and γ/γ′ interfacial dislocations during high-temperature, low-stress creep of a nickel-based single-crystal superalloy
TL;DR: In this paper, a detailed characterization of interfacial dislocations in a DD6 superalloy after 12h at high temperature and low stress was carried out using transmission electron microscopy and high-angle annular dark field scanning transmission electron microscope techniques.
Journal ArticleDOI
Phase field study of precipitate rafting under a uniaxial stress
M. P. Gururajan,T.A. Abinandanan +1 more
TL;DR: In this article, a phase field model of an elastically inhomogeneous alloy was used to calculate elastic stress and strain fields for two-phase microstructures under a uniaxial applied stress.
Journal ArticleDOI
Observations of a〈0 1 0〉 dislocations during the high-temperature creep of Ni-based superalloy single crystals deformed along the [0 0 1] orientation
TL;DR: A NASAIR-100 superalloy single crystal was tested in tension creep at 1000°C at a stress of 148 MPa, for a time period of 20h and to a strain of 1.1% as mentioned in this paper.
Journal ArticleDOI
Atom probe informed simulations of dislocation-precipitate interactions reveal the importance of local interface curvature
Aruna Prakash,Julien Guénolé,J. Wang,Julian George Müller,Erdmann Spiecker,Michael J. Mills,Ivan Povstugar,Pyuck-Pa Choi,Dierk Raabe,Erik Bitzek +9 more
TL;DR: In this paper, the authors used atomistic simulation samples generated from atom probe tomography data of a single crystal superalloy to study the interactions of matrix dislocations with a γ ′ precipitate in molecular dynamics simulations.
References
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Journal ArticleDOI
Directional coarsening of γ′ phase in single crystal nickel based superalloys during tensile creep
TL;DR: In this article, the gamma precipitate rafting kinetics and morphological evolution for two model single crystal superalloys have been studied and the microstructure of the alloys after different stages of tensile creep at 1040 degrees C and under a range of stresses are examined using TEM and SEM.
Journal ArticleDOI
The chemical driving force for rafting in superalloys
TL;DR: In this paper, the authors considered only the change in enthalpy between two states, one in which the two phases have the compositions which are in equilibrium in the absence of external stress, the external stress has been applied, but no diffusion has occurred, and the other one has the homogeneous compositions under the applied stress.
Journal ArticleDOI
Finite Element Stress and strain analysis of a double shear creep specimen
TL;DR: Mayr et al. as mentioned in this paper reported on creep stress and strain results obtained by the finite element method (FEM) for a double shear specimen which was recently developed, considering stress redistribution during creep, small changes in specimen geometry during testing and high local stress states at the positions where the specimen is loaded.