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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Enhanced strength-ductility synergy in a novel V-containing γ″-strengthened CoCrNi-based multi-component alloy
TL;DR: In this article, the existence of γ-phase precipitates in V-containing CoCrNi-based alloys was identified, where moderate γ/γ lattice misfit results in good combination of coherency-strengthening and coarsening-resistance.
Journal ArticleDOI
Atom Probe Microscopy of Strengthening Effects in Alloy 718.
TL;DR: Recognizing the importance of the precipitate stacking order, the different types of precipitate interfaces are quantified, and these methods may be applicable to other engineering alloys.
Journal ArticleDOI
A Microstructure-Based Time-Dependent Crack Growth Model for Life and Reliability Prediction of Turbopropulsion Systems
TL;DR: In this article, a set of generic microstructure-based time-dependent crack growth (TDCG) models was developed and used to assess the sources of material variability due to micro-structure and material parameters such as grain size, activation energy, and crack growth threshold for TDCG.
Journal ArticleDOI
Microstructure evolution and mechanical property characterization of a nickel-based superalloy at the mesoscopic scale
TL;DR: In this article, the microstructure evolution of the γ″ phase and the tensile mechanical properties of a nickel-based superalloy at the mesoscopic scale were investigated systematically.
Journal ArticleDOI
Mechanical Properties Evolution of γ′/γ″ Nickel-Base Superalloys During Long-Term Thermal Over-Aging
TL;DR: In this article, the long-term stability of Inconel 718 and Waspaloy forgings in the 600°C to 850°C temperature range and up to 10,000 hours was studied by means of mechanical tests and microstructural analyses.
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.