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
Citations
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Journal ArticleDOI
Determination of Anisotropic Mechanical Properties for Materials Processed by Laser Powder Bed Fusion
TL;DR: In this article, a tensile test of flat specimens manufactured by laser powder bed fusion (LPBF) at different orientations relative to the build plate was performed on the Inconel 718 alloy.
Journal ArticleDOI
Time-Dependent Crack Growth Thresholds of Ni-Base Superalloys
TL;DR: In this paper, a micromechanical model has been developed for predicting the time-dependent crack growth threshold and its variability by considering oxide formation or cavity formation ahead of an elastic crack subjected to a sustained load at a stress intensity factor, K, at elevated temperatures in air.
Proceedings ArticleDOI
The high temperature stability of in718 derivative alloys
TL;DR: Ticolloy as discussed by the authors is an alloy developed through a systematic variation of the Al/l? and (Al+Ti )/Nb atomic ratios, which exhibited improved strength and high temperature stability, however, hydrogen susceptibility and crack growth behavior showed no improvement.
Journal ArticleDOI
Defect tolerance and hydrogen susceptibility of the fatigue limit of an additively manufactured Ni-based superalloy 718
Kevinsanny,Saburo Okazaki,Osamu Takakuwa,Yuhei Ogawa,Yusuke Funakoshi,Hideto Kawashima,Saburo Matsuoka,Hisao Matsunaga +7 more
TL;DR: In this paper, the sensitivity of Ni-based superalloy 718 samples to surface finishing conditions and solute hydrogen was investigated via a series of tension-compression fatigue tests.
Journal ArticleDOI
Overlapping of γ′ precipitate variants in Inconel 718
M. Sundararaman,P. Mukhopadhyay +1 more
TL;DR: Inconel 718 alloy, different variants of γ′ precipitates often appear to intersect each other during their growth as mentioned in this paper, and such apparent intersections are shown on the basis of structure factor contrast to be an overlapping effect.
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.