Investigations of MX and γ′/γ″ precipitates in the nickel-based superalloy 718 produced by electron beam melting

Strondl, Annika; Fischer, R.; Frommeyer, G.; Schneider, A.

doi:10.1016/j.msea.2007.07.012

Cited by 154 publications

(83 citation statements)

References 10 publications

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“…[22] Similar columns of small (~10 nm) c¢¢ (Ni 3 Nb) precipitates coincident with {100} c have also been observed in the EBM fabrication of an INCONEL 718 alloy by Strondl et al [23] In the microstructural architectures of precipitate arrays observed in EBMfabricated materials, including Figures 3 and 4, the arrays were characterized by columnar precipitate geometries spaced~2 to 3 lm [17,22] or larger. [23] These features are created by the EBM-beam scans, which include rapid multipass, orthogonal (x-y), fixed spatial rastering of the beam to preheat the layers, as well as the final x-y melt scan. [17,22] The orthogonally rastered zones create thermal partitioning in each layer, conducive to precipitation, which is additively extended forming the columnar architectures.…”

Section: Resultssupporting

confidence: 68%

“…As noted earlier, aged alloys 718 and 625 can produce fcc and bct Ni 3 Nb disc and cubic precipitates coincident with the fcc (Ni-Cr) matrix {100} planes including the recent EBM work by Strondl et al [23] In addition, other Ni-base superalloy compositions commonly also produce fcc Ni 3 Cr-2 and bct Ni 4 Mo precipitates. [3,4,7,14,23] XRD analysis for the precursor powder is reproduced in Figure 5(a).…”

Section: Resultsmentioning

confidence: 77%

“…[3,4,7,14,23] XRD analysis for the precursor powder is reproduced in Figure 5(a). Since the dendritic (microdendritic) structure for the alloy 625 precursor powder does not exhibit any precipitation features (Figure 2), the spectral indices indicated are coincident with solid-solution fcc NiCr (a = 0.359 nm; space group: Fm-3m).…”

Section: Resultsmentioning

confidence: 99%

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Microstructural Architecture, Microstructures, and Mechanical Properties for a Nickel-Base Superalloy Fabricated by Electron Beam Melting

Murr

Martínez

Gaytan

et al. 2011

Metall Mater Trans A

240

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Microstructures and a microstructural, columnar architecture as well as mechanical behavior of as-fabricated and processed INCONEL alloy 625 components produced by additive manufacturing using electron beam melting (EBM) of prealloyed precursor powder are examined in this study. As-fabricated and hot-isostatically pressed (''hipped'') [at 1393 K (1120°C)] cylinders examined by optical metallography (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive (X-ray) spectrometry (EDS), and X-ray diffraction (XRD) exhibited an initial EBM-developed c¢¢ (bct) Ni 3 Nb precipitate platelet columnar architecture within columnar [200] textured c (fcc) Ni-Cr grains aligned in the cylinder axis, parallel to the EBM build direction. Upon annealing at 1393 K (1120°C) (hot-isostatic press (HIP)), these precipitate columns dissolve and the columnar, c, grains recrystallized forming generally equiaxed grains (with coherent {111} annealing twins), containing NbCr 2 laves precipitates. Microindentation hardnesses decreased from~2.7 tõ 2.2 GPa following hot-isostatic pressing (''hipping''), and the corresponding engineering (0.2 pct) offset yield stress decreased from 0.41 to 0.33 GPa, while the UTS increased from 0.75 to 0.77 GPa. However, the corresponding elongation increased from 44 to 69 pct for the hipped components.

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Section: Resultssupporting

confidence: 68%

Section: Resultsmentioning

confidence: 77%

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Microstructural Architecture, Microstructures, and Mechanical Properties for a Nickel-Base Superalloy Fabricated by Electron Beam Melting

Murr

Martínez

Gaytan

et al. 2011

Metall Mater Trans A

240

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“…Currently, the major EBM Ni-base superalloy research is focus on IN718 [53,[74][75][76][77][78] and IN625 [79,80] because of their weldabilities. However, the relatively high chamber temperature during process enables the possibility of manufacturing those γ ′ strengthened Ni-based superalloy.…”

Section: Materials Manufactured With Ebmmentioning

confidence: 99%

“…Strondl et al [74] reported the very first research on EBM IN718. This asmanufactured EBM IN718 has the γ grains elongated along the building direction and ⟨100⟩ building direction texture.…”

Section: Ebm In718mentioning

confidence: 99%

Additively Manufactured Inconel 718 : Microstructures and Mechanical Properties

Deng

2018

Linköping Studies in Science and Technology. Licentiate Thesis

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Linköping 2018Cover image: A fracture surface of EBM IN718 after tensile test at room temperature.During the course of research underlying this thesis, Dunyong Deng was enrolled in Agora Materiae, a multidiciplinary doctoral program at Linköping University, Sweden. Printed by LiU-Tryck 2018 © Dunyong Deng AbstractAdditive manufacturing (AM), also known as 3D printing, has gained significant interest in aerospace, energy, automotive and medical industries due to its capabilities of manufacturing components that are either prohibitively costly or impossible to manufacture by conventional processes. Among the various additive manufacturing processes for metallic components, electron beam melting (EBM) and selective laser melting (SLM) are two of the most widely used powder bed based processes, and have shown great potential for manufacturing high-end critical components, such as turbine blades and customized medical implants. The futures of the EBM and SLM are doubtlessly promising, but to fully realize their potentials there are still many challenges to overcome.Inconel 718 (IN718) is a nickel-base superalloy and has impressive combination of good mechanical properties and low cost. Though IN718 is being mostly used as a turbine disk material now, the initial introduction of IN718 was to overcome the poor weldability of superalloys in 1960s, since sluggish precipitation of strengthening phases γ ′ /γ ′′ enables good resistance to strain-age cracking during welding or post weld heat treatment. Given the similarity between AM and welding processes, IN718 has been widely applied to the metallic AM field to facilitate the understandings of process-microstructure-property relationships.The work presented in this licentiate thesis aims to better understand microstructures and mechanical properties EBM and SLM IN718, which have not been systematically investigated. Microstructures of EBM and SLM IN718 have been characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and correlated with the process conditions. Monotonic mechanical properties (e.g., Vickers microhardness and tensile properties) have also been measured and rationalized with regards to the microstructure evolutions before and after heat treatments.For EBM IN718, the results show the microstructure is not homogeneous but dependant on the location in the components, and the anisotropic mechanical properties are probably attributed to alignment of porosities rather than texture.iii Post heat treatment can slightly increase the mechanical strength compared to the as-manufactured condition but does not alter the anisotropy. SLM IN718 shows significantly different microstructure and mechanical properties to EBM IN718. The as-manufactured SLM IN718 has very fine dendritic microstructure and Laves phases in the interdendrites, and is "work-hardened" by the residual strains and dislocations present in the material. Mechanical properties are different between horizontally and vertically built samples, and heat treatment can m...

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