Journal ArticleDOI
Morphology of y’ and y” precipitates and thermal stability of inconel 718 type alloys
R. Cozar,André Pineau +1 more
- Vol. 4, Iss: 1, pp 47-59
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TLDR
In this article, the precipitation microstructure varies rapidly with aging temperature and composition, and the influence of composition and aging temperature on the conditions that bring about this compact morphology has been investigated.Abstract:
The precipitation of the γ’ (Ll2) and γ" (DO22) phases has been studied in four alloys Fe-Ni-Cr-Ti-Al-Nb containing a higher Ti + Al/Nb ratio than that of the INCONEL 718 alloy. For these alloys, the precipitation microstructure varies rapidly with aging temperature and composition. Bct γ"particles have always been found to precipitate on γ’ phase. Moreover, by aging three alloys above a critical temperature, a “compact ntorphology” has been observed: cube-shaped γ’ particles coated on their six faces with a shell of γ" precipitate. This microstructure has proved to be very stable on prolonged aging. A thermal stability better than that encountered in nominal INCONEL 718 alloy can thus be achieved. The influence of composition and aging temperature on the conditions that bring about this “compact morphology” has been investigated. A minimal Ti + Al/Nb ratio between 0.9 and 1 has been determined, allowing the “compact morphology” to be obtained.read more
Citations
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Journal ArticleDOI
A Review of Methodology Development for Controlling Loss of Alloying Elements During the Electroslag Remelting Process
TL;DR: In this article, the authors summarized previous knowledge on the controlling loss reactive elements during ESR of Fe- and Ni-based alloys in view of thermodynamics and kinetics, which can guide the development of a new remelting technique that retards the oxidation of Al and Ti in Inconel 718 alloys during the ESR process.
Book ChapterDOI
Ni-Based Alloys for Reactor Internals and Steam Generator Applications
TL;DR: In this article, the effect of neutron irradiation on Ni-alloy performance has been considered and the most important aspect of in-core behavior of Ni alloys is the fact that transmutation of the main natural isotope, 58Ni, to 59Ni results in enhanced radiation-induced degradation that is unique to Ni among common engineering alloys.
Journal ArticleDOI
Phase-field modeling of γ/γ″ microstructure formation in Ni-based superalloys with high γ″ volume fraction
TL;DR: In this article, a phase-field model was used to investigate various influencing factors that determine the equilibrium shapes of Ni-based superalloy IN718 precipitates, minimizing the sum of the total elastic and interfacial energy.
Proceedings ArticleDOI
Influence of compositional modifications on thermal stability of alloy 7 18.
TL;DR: In this article, a comparison of Alloy 718 and Alloy 976M was made on the basis of hardness measurements and microstructural modifications resulting from long term aging (10 000 hours) applied at three temperatures (650°C-700°C -75O’C).
Journal ArticleDOI
DFT study of the solubility of hydrogen and carbon in Ni3Nb-D0a and Ni3Nb-D022 systems
TL;DR: In this paper, the influence of local environment on C and H atoms was investigated in Ni3Nb-D0a and D022 (space group 59) and their solubility energies were studied by analyzing the results of first-principles calculations based on density functional theory.
References
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Journal ArticleDOI
The Determination of the Elastic Field of an Ellipsoidal Inclusion, and Related Problems
TL;DR: In this paper, it is shown that to answer several questions of physical or engineering interest, it is necessary to know only the relatively simple elastic field inside the ellipsoid.
Journal ArticleDOI
Déformations de cohérence d'un précipité quadratique
TL;DR: In this paper, exact expressions for the elastic field due to a perfectly coherent precipitate having the form of a rectangular parallelepiped, the material being supposed elastically homogeneous and isotropic.
Journal ArticleDOI
The microstructure of 706, a new Fe−Ni-base superalloy
TL;DR: In this article, the phase relationships of Alloy 706 alloy were investigated and it was shown that on the basis of chemistry and micro-structural response, Alloy 606 alloy can be considered to be intermediate to the well-known alloys, 718 and 901.
Journal ArticleDOI
Heterogeneous precipitation of metastable γ′-ni3ti in a nickelbase alloy
TL;DR: In this article, the effect of prior deformation on the precipitation of L12 γ′-Ni3Ti in nickel-base Alloy 901 was investigated by thin foil microscopy.
Journal ArticleDOI
Fine Faults and Crystal Structures of Precipitates in Fe-Mo and Fe-W Alloys
Kōhei Yagisawa,Hiroshi Fujita +1 more
TL;DR: In this paper, the crystal structure and two-dimensional faults of the precipitates in Fe-Mo alloys were investigated using electron microscopic method, and the faults were found on {00.1}hex, {10.0}hex and {100}hex planes.