Precipitation of γ′ phase in δ-precipitated Alloy 718 during deformation at elevated temperatures

Nalawade, Sachin; Sundararaman, M.; Singh, J.B.; Verma, Amit Kumar; Kishore, R.

doi:10.1016/j.msea.2010.01.006

Cited by 44 publications

(13 citation statements)

References 6 publications

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“…[57][58][59] Therefore, in the current study, we focused on the behavior of M 23 C 6 phase in both annealed and strained conditions. In Figure 7, the annealed conditions and strained conditions were assigned by square and circle symbols, respectively.…”

Section: Ttp Diagram Of M 23 C 6 In Annealed and Strained Conditionsmentioning

confidence: 99%

Identification of Mo-Rich M23C6 Carbides in Alloy 718

Aghajani¹,

Tewes²,

Parsa

et al. 2016

Metall Mater Trans A

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In the present study, we systematically identify and characterize a (Nb, Mo)-rich M 23 C 6 type of M 23 C 6 carbide with a lattice parameter of 1.094 nm in alloy 718 for the first time using a combination of selected area electron diffraction pattern and powder X-ray diffraction analysis. The time-temperature-precipitation diagrams of the precipitates in both annealed and strained conditions are obtained by particle analysis using an automated scanning electron microscopy method. (Nb, Mo)-rich M 23 C 6 carbides first precipitate after 24 hours at 1223 K (950°C) annealing, while they form after 10 minutes at 1273 K (1000°C) in the strained condition. This correlates with the excess dislocations produce during deformation.

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Section: Ttp Diagram Of M 23 C 6 In Annealed and Strained Conditionsmentioning

confidence: 99%

Identification of Mo-Rich M23C6 Carbides in Alloy 718

Aghajani¹,

Tewes²,

Parsa

et al. 2016

Metall Mater Trans A

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“…in the aerospace industry [1,2]. Generally, Inconel 718 alloy is strengthened by the precipitation of metastable γ′ (Ni 3 Al) coupled with γ″ (Ni 3 Nb) phases and the coherent disc-shaped γ″-phase is the major strengthening phase [3,4]. The orthorhombic incoherent δ-phase (Ni 3 Nb) is the equilibrium phase corresponding to γ″-phase, which has higher stability at elevated temperature [5].…”

Section: Introductionmentioning

confidence: 99%

Precipitation behavior during high-temperature isothermal compressive deformation of Inconel 718 alloy

Zhang

Liu

et al. 2016

Materials Science and Engineering: A

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The precipitation behaviors of γ″ and δ phases during high-temperature isothermal compressive deformation of Inconel 718 alloy are investigated under the strain rate of 2.2·10 -4 s -1 . It is found that the precipitation behaviors are tailored by deformation temperatures, and lead to the disparately abnormal deformation characteristics. Under the deformation temperature of 800 o C, the microstructure is composed of incoherent needle-shaped γ″ precipitates at grain boundaries and ultrafine spherical γ″ particles within grains, resulting in the exceptional decrease of flow stress with absence of DRX. When deformed at 900 o C, it becomes needle-shaped δ precipitates at grain boundaries and intragranular disc-shaped γ″ precipitates, and the DRX softening degree is lowered consequently.

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“…In the case of DELTA microstructure, only γ′ at T = 600° C and γ′ and γ" at T = 700° C have precipitated in the deformed specimens. These observations are rationalized on the basis of the relative concentration of Al, Ti and Nb in the matrix of δ precipitated Alloy 718 microstructure [21].…”

Section: Deformation Microstructurementioning

confidence: 85%

Serrated Yielding in Alloy 718

Verma¹,

Singh²,

Ramaswamy³

et al. 2010

7th International Symposium on Superalloy 718 and Derivatives (2010)

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Alloy 718 has been reported to undergo serrated yielding (SY) phenomenon over the temperature regime that coincides with its useful service temperature range. The SY is reported to reduce ductility in several alloy systems. The present paper reports the results of detailed investigation carried out on SY phenomenon in Alloy 718 in three different microstructural conditions viz. solution annealed (ST), γ′′ precipitated (STA) and δ precipitated (DELTA). Based on the estimated activation energy for appearance and disappearance of serrations as well as the nature of serrations, two regimes of dynamic strain ageing (DSA) have been identified -one below 525° C controlled by diffusion of interstitial carbon and the other above 525° C controlled by diffusion of substitutional niobium atom. The initial microstructure appeared to strongly influence the temperature regime of serrated flow. The mechanism for the delayed disappearance of serrations in ST specimens has been identified from TEM examination of deformed specimens.

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Precipitation of γ′ phase in δ-precipitated Alloy 718 during deformation at elevated temperatures

Cited by 44 publications

References 6 publications

Identification of Mo-Rich M23C6 Carbides in Alloy 718

Identification of Mo-Rich M23C6 Carbides in Alloy 718

Precipitation behavior during high-temperature isothermal compressive deformation of Inconel 718 alloy

Serrated Yielding in Alloy 718

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