Multiscale microstructural heterogeneity and mechanical property scatter in Inconel 718 produced by directed energy deposition

Yeoh, Yong Chen; Macchi, G.; Jain, Ekta; Gaskey, Bernard; Raman, Sudharshan; Tay, Grace; Verdi, Davide; Patran, A.; Grande, Antonio Mattia; Seita, Matteo

doi:10.1016/j.jallcom.2021.161426

Cited by 31 publications

(8 citation statements)

References 41 publications

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“…Typically, grain growth is more favorable when the maximum heat ow direction closely aligns with one of the easy-growth directions, < 100 > for Ni, referred to as competitive growth. However, in certain laser scanning patterns, the actual direction of grain growth may deviate signi cantly from the local maximum temperature gradient due to various cooling rates in different areas [40,41]. The difference between the cooling rates in various areas in P4 is more obvious than in P2 and P3.…”

Section: Grain Structurementioning

confidence: 99%

Effect of infill passes on the microstructure evolution of Inconel 718 thin walls produced using laser-directed energy deposition

Khodamoradi,

Jones,

Wall

et al. 2024

Preprint

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Laser-Directed Energy Deposition (L-DED) is an additive manufacturing technique that, in addition to fabricating new parts, is especially adept at creating and repairing thin-wall structures. This study explores the effects of the number of infill passes on the microstructure and mechanical properties of Inconel 718 thin walls fabricated by L-DED. The effects of spatially varying cooling rates across both height above the substrate and through the thickness of the thin-wall samples, quantified through a combination of dendrite arm spacing measurements and finite element simulations, revealed that the most rapid cooling occurred at the walls' base under all conditions. The number of infill passes had a significant effect on this behavior, with no infill pass condition showing the most uniform cooling rate through its height. Moreover, the microstructure variation resulted in spatially varying hardness ranging from 170 HV in the stainless steel substrate to ~ 220 HV towards the skin and top of the samples and finally up to ~ 270 HV in the center of the samples where the cooling rate was high. It is concluded that the infill pass strategy is a critical parameter in the L-DED process that directly influences the thermal history and, thus, the resultant microstructure of Inconel 718 thin walls.

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Section: Grain Structurementioning

confidence: 99%

Effect of infill passes on the microstructure evolution of Inconel 718 thin walls produced using laser-directed energy deposition

Khodamoradi,

Jones,

Wall

et al. 2024

Preprint

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“…These ''microstructure architectures'', however, are typically restricted to small scale materials because of the limitations associated with the respective manufacturing processes. With AM, these microstructure designs may be extended to bulk materials containing site-specific textures [41], directional solidification structures [79], dissimilar grain structures [80], composition gradients [81], and multiple phases [71]. In the context of A-GBE, site-specific microstructure control could be used to engineer the density of nucleation sites for recrystallisation across the build-for instance by selectively weakening the solidification structure.…”

Section: Site-specific A-gbementioning

confidence: 99%

Broadening the design space of engineering materials through “additive grain boundary engineering”

Seita

Gao

2022

J Mater Sci

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Grain boundary engineering (GBE) is one of the most successful processing strategies to improve the properties of polycrystalline solids. However, the extensive thermomechanical processes involved during GBE restrict its use to selected applications and materials. In this viewpoint paper, we discuss the opportunity provided by additive manufacturing (AM) technology to broaden the applicability of the GBE paradigm and, consequently, the design space for engineering materials. By integrating specially-designed thermomechanical processing within AM, it would be possible to produce bulk, near-net-shape parts with complex geometry and GBE microstructure. We discuss the major challenges in this endeavor and propose some possible strategies to achieve this goal, which we refer to as “additive-GBE”.

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“…The performance improvements stem from the additional strengthening mechanisms brought about by the formation of solidification cellular structures [8,11], suppression of second-phase precipitates [9], and phase stability of the material during deformation [10], which are ascribed to the non-equilibrium cooling conditions of the AM process. Furthermore, AM enables structural materials with unprecedented property tuning through composition [12] or microstructure adjustments [13,14]. These adjustments can be tailored locally by varying the process parameters or feedstock material point-by-point in the printed part.…”

Section: Introductionmentioning

confidence: 99%

Laser powder bed fusion of high-strength and corrosion-resistant Inconel alloy 725

Todaro

Rashidi

Liu

et al. 2022

Materials Characterization

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Multiscale microstructural heterogeneity and mechanical property scatter in Inconel 718 produced by directed energy deposition

Cited by 31 publications

References 41 publications

Effect of infill passes on the microstructure evolution of Inconel 718 thin walls produced using laser-directed energy deposition

Effect of infill passes on the microstructure evolution of Inconel 718 thin walls produced using laser-directed energy deposition

Broadening the design space of engineering materials through “additive grain boundary engineering”

Laser powder bed fusion of high-strength and corrosion-resistant Inconel alloy 725

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