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
Reads0
Chats0
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
More filters
Book ChapterDOI
Research on Inconel 718 Type Alloys with Improvement of Temperature Capability
TL;DR: Inconel 718 was developed by International Nickel Company in 1962, and has become the most widely used superalloy in the world as discussed by the authors. But, its maximum use temperature is restricted to 650oC because the main strengthening γ′′ phase responsible for the alloy's outstanding properties rapidly overages.
Book ChapterDOI
Stress Corrosion Cracking Behavior of Alloy 718 Subjected to Various Thermal Mechanical Treatments in Primary Water
TL;DR: In this article, the SCC behavior of alloy 718 in three different thermal mechanical treatments (TMTs) and two different heats was studied in PWR primary water environment using constant extension rate tensile (CERT) tests.
Posted ContentDOI
Studies of Post Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins and Hardness
Wakshum Mekonnen Tucho,V. Hansen +1 more
Abstract: The widely adopted temperature for solid solution heat treatment (ST) for the conventionally fabricated Inconel 718 is 1100 °C for a hold time of 1 h or less. This ST scheme is however not enough to dissolve Laves and annihilate dislocations completely in samples fabricated with Laser metal powder bed fusion (L-PBF) additive manufacturing (AM)-Inconel 718. In spite this, the highest hardness obtained after aging for ST temperatures (970 1250 °C) is at 1100 °C/1h [1]. The unreleased residual stresses in the retained lattice defects are potentially affecting other properties of the material. Hence, this work aims to investigate if a longer hold time of ST at 1100 °C will lead to complete recrystallization while maintaining the strength after aging or not. For this study, L-PBFInconel 718 samples were ST at 1100 °C at various hold times (1, 3, 6, 9, 16 or 24 h) and aged to study the effects on microstructure and hardness. In addition, a sample was directly aged to study the effects of bypassing ST. The samples (ST and aged) gain hardness by 43 – 49 %. High density of annealing twins evolved during 3 h of ST and only slightly varies for longer ST.
Dissertation
Development of post-deposition heat treatment to improve mechanical properties of wire-arc additive manufactured ATI 718Plus superalloy
TL;DR: In this paper, the authors present a collection of tables, columns, and figures from the paper "Thesis Layout: A LITERATURE this paper : A Review of Thesis Layout".
Book ChapterDOI
Effect of Homogenization on Creep of Additive Manufactured Alloy 718
Tomoki Otsuka,H. Wakabayashi,Daisuke Igarashi,Achmad Ariaseta,Shinya Imano,Yuting Wang,Satoru Kobayashi,Masao Takeyama +7 more
TL;DR: In this paper, three types of homogenization (solution) treatments, 982 °C, 1060 °C and 1200 °C for 2 h, were employed, prior to the standard aging treatment known as supersolvus aging in the wrought alloy.
References
More filters
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.