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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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
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Book ChapterDOI
Evolution of δ Phase Microstructure in Alloy 718
TL;DR: In this paper, the authors reported the results of a detailed microstructural investigation carried out using Transmission Electron Microscopy (TEM) and Scanning Electron microscopy (SEM) on the evolution of δ microstructure.
Journal ArticleDOI
High-temperature structure stability and mechanical properties of novel 718 superalloy
TL;DR: In this paper, a kind of novel 718 alloy, which offers 30°C temperature advantage over conventional In 718, was designed and fabricated by adjustment of chemical composition which included the increasing in content of Al+Ti, the ratio of Al/Ti and the level of P and B.
Journal ArticleDOI
Effects of pressure on anisotropic elastic properties and minimum thermal conductivity of D022-Ni3Nb phase: First-principles calculations
TL;DR: In this article, the effects of pressure on anisotropic elastic properties and minimum thermal conductivity of D022-Ni3Nb phase at different pressures are discussed in detail.
Journal ArticleDOI
INCOLOY 908, a low coefficient of expansion alloy for high-Strength cryogenic applications: Part I. Physical metallurgy
TL;DR: A detailed analysis of precipitated phases has been conducted using X-ray diffraction (XRD), transmission electron microscopy (TEM), and analytical scanning and scanning transmission electron microscope (STEM) techniques as discussed by the authors.
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.