Microstructural Development in Inconel 718 Nickel-Based Superalloy Additively Manufactured by Laser Powder Bed Fusion

Huynh, Thinh; Mehta, Abhishek; Graydon, Kevin; Woo, Jeong-Min; Park, Sharon K.; Hyer, Holden; Zhou, Le; Imholte, D. Devin; Woolstenhulme, Nicolas E.; Wachs, Daniel M.; Sohn, Yongho

doi:10.1007/s13632-021-00811-0

Cited by 20 publications

(4 citation statements)

References 48 publications

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“…Basically, about 2/5 of the bottom nucleated grains will survive in this 3-layer 5-track simulated AM geometry for P = 188 W. It can also be noted from Figures 7 and 8 that the grain size is larger for P = 125 W as compared with all the other power levels, where the grain size is somewhat similar. Based on these simulations, the optimal power levels in terms of power efficiency, grain size and porosity reduction are the range of 175-200 W. This is in line with the experimental observations [1][2][3][4].…”

Section: Resultssupporting

confidence: 84%

“…The aim of this study was to model quickly and efficiently the microstructure evolution as well as pores and densification issues of IN718 alloy during the laser powder bed fusion (LPBF). The effect of laser scanning speed and power on the formation of IN718 microstructure, keyhole porosity, interlayer voids, and lack of fusion defects were studied in [1][2][3][4][5]. The effect of hatch spacing on the amount of lack of fusion voids was studied in [5] for a 5-layers 5-hatches IN718 build processed by LPBF.…”

Section: Introductionmentioning

confidence: 99%

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3D Modeling of the Solidification Structure Evolution and of the Inter Layer/Track Voids Formation in Metallic Alloys Processed by Powder Bed Fusion Additive Manufacturing

Nastac

2022

Materials

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A fully transient discrete-source 3D Additive Manufacturing (AM) process model was coupled with a 3D stochastic solidification structure model to simulate the grain structure evolution quickly and efficiently in metallic alloys processed through Electron Beam Powder Bed Fusion (EBPBF) and Laser Powder Bed Fusion (LPBF) processes. The stochastic model was adapted to rapid solidification conditions of multicomponent alloys processed via multi-layer multi-track AM processes. The capabilities of the coupled model include studying the effects of process parameters (power input, speed, beam shape) and part geometry on solidification conditions and their impact on the resulting solidification structure and on the formation of inter layer/track voids. The multi-scale model assumes that the complex combination of the crystallographic requirements, isomorphism, epitaxy, changing direction of the melt pool motion and thermal gradient direction will produce the observed texture and grain morphology. Thus, grain size, morphology, and crystallographic orientation can be assessed, and the model can assist in achieving better control of the solidification microstructures and to establish trends in the solidification behavior in AM components. The coupled model was previously validated against single-layer laser remelting IN625 experiments performed and analyzed at National Institute of Standards and Technology (NIST) using LPBF systems. In this study, the model was applied to predict the solidification structure and inter layer/track voids formation in IN718 alloys processed by LPBF processes. This 3D modeling approach can also be used to predict the solidification structure of Ti-based alloys processes by EBPBF.

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Section: Resultssupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

3D Modeling of the Solidification Structure Evolution and of the Inter Layer/Track Voids Formation in Metallic Alloys Processed by Powder Bed Fusion Additive Manufacturing

Nastac

2022

Materials

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“…At least ten samples extracted on each direction were investigated per each process parameters set. The samples were extracted at different positions along the specimen's length to highlight any potential microstructural heterogeneity along the build direction [65,66].…”

Section: Microstructural Analysismentioning

confidence: 99%

Impact of process parameters on the dynamic behavior of Inconel 718 fabricated via laser powder bed fusion

Abruzzo,

Macoretta,

Monelli

et al. 2024

Int J Adv Manuf Technol

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In this research, we investigate the dynamic behavior of Inconel 718 fabricated through laser powder bed fusion (L-PBF), addressing a notable knowledge gap regarding the correlation between process parameters and dynamic properties. The process parameters adopted are deducted from an extension of the Rosenthal solution, formulated to increase the process productivity while avoiding the typical production process defects. The dynamic Young modulus and the structural damping of the material are estimated as a function of the process parameters through ping tests reproducing the flexural vibrations of the specimens in as-built, solutioned, and aged conditions. The microstructure and porosity are investigated through metallographic analyses. The results show a substantial influence of the L-PBF process parameters on the dynamic Young modulus, which markedly increases as the energy density is reduced (23%) and progressively becomes more similar to the conventionally produced material. This influence stands in stark contrast to the relatively modest impact of heat treatments, which underlines a negligible effect of the process-induced residual stress. The structural damping remained approximately constant across all test conditions. The elastic response of the material is found to be primarily influenced by the different microstructures produced as the L-PBF process parameters varied, particularly in terms of the dimensions and shape of the solidification structures. The unexpected relationship between the dynamic Young modulus, energy density, and microstructure unveils the potential to fine-tune the material’s dynamic behavior by manipulating the process parameters, thereby carrying substantial implications for all the applications of additively manufactured components susceptible to significant vibratory phenomena.

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“…For instance, LOM has been used to show that the meander scanning strategy generates a finer and more homogeneous distribution of melt pools in comparison to chessboard strategy in IN718 [223]. Higher laser power produces deeper melt pools while faster scan speeds make the melt pool shallower [227]. Other features of interest such as pores and cracks can be observed in polished surfaces [228], while additional microstructural constituents such as grain and melt pool boundaries might require chemical etching to be revealed [229].…”

Section: Optical Microscopymentioning

confidence: 99%

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

et al. 2022

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Metal additive manufacturing (AM) has unlocked unique opportunities for making complex Ni-based superalloy parts with reduced material waste, development costs, and production lead times. Considering the available AM methods, powder bed fusion (PBF) processes, using either laser or electron beams as high energy sources, have the potential to print complex geometries with a high level of microstructural control. PBF is highly suited for the development of next generation components for the defense, aerospace, and automotive industries. A better understanding of the as-built microstructure evolution during PBF of Ni-based superalloys is important to both industry and academia because of its impacts on mechanical, corrosion, and other technological properties, and, because it determines post-processing heat treatment requirements. The primary focus of this review is to outline the individual phase formations and morphologies in Ni-based superalloys, and their correlation to PBF printing parameters. Given the hierarchal nature of the microstructures formed during PBF, detailed descriptions of the evolution of each microstructural constituent are required to enable microstructure control. Ni-based superalloys microstructures commonly include γ, γ′, γ′′, $$\delta$$ δ , TCP, carbides, nitrides, oxides, and borides, dependent on their composition. A thorough characterization of these phases remains challenging due to the multi-scale microstructural hierarchy alongside with experimental challenges related to imaging secondary phases that are often nanoscale and (semi)-coherent. Hence, a detailed discussion of advanced characterization techniques is the second focus of this review, to enable a more complete understanding of the microstructural evolution in Ni-based superalloys printed using PBF. This is with an expressed goal of directing the research community toward the tools necessary for a thorough investigation of the processing-microstructure-property relationships in PBF Ni-based superalloy parts to enable microstructural engineering.

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Microstructural Development in Inconel 718 Nickel-Based Superalloy Additively Manufactured by Laser Powder Bed Fusion

Cited by 20 publications

References 48 publications

3D Modeling of the Solidification Structure Evolution and of the Inter Layer/Track Voids Formation in Metallic Alloys Processed by Powder Bed Fusion Additive Manufacturing

3D Modeling of the Solidification Structure Evolution and of the Inter Layer/Track Voids Formation in Metallic Alloys Processed by Powder Bed Fusion Additive Manufacturing

Impact of process parameters on the dynamic behavior of Inconel 718 fabricated via laser powder bed fusion

Powder bed fusion additive manufacturing of Ni-based superalloys: a review of the main microstructural constituents and characterization techniques

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