Powder bed binder jet 3D printing of Inconel 718: Densification, microstructural evolution and challenges☆

In the present study, multi-objective optimization is employed to develop the optimum heat treatments that can achieve both high-mechanical performance and non-distinctive crystallographic texture of 3D printed Inconel 718 (IN718) fabricated by laser powder bed fusion (LPBF). Heat treatments including homogenization at different soaking times (2, 2.5, 3, 3.5 and 4 h) at 1080 °C, followed by a 1 h solution treatment at 980 °C and the standard aging have been employed. 2.5 h is found to be the homogenization treatment threshold after which there is a depletion of hardening precipitate constituents (Nb and Ti) from the γ-matrix. However, a significant number of columnar grains with a high fraction (37.8%) of low-angle grain boundaries (LAGBs) have still been retained after the 2.5 h homogenization treatment. After a 4 h homogenization treatment, a fully recrystallized IN718 with a high fraction of annealing twins (87.1%) is obtained. 2.5 and 4 h homogenization treatments result in tensile properties exceeding those of the wrought IN718 at both RT and 650 °C. However, considering the texture requirements, it is found that the 4 h homogenization treatment offers the optimum treatment, which can be used to produce IN718 components offering a balanced combination of high mechanical properties and adequate microstructural isotropy.

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Binder-jet powder-bed additive manufacturing (3D printing) of thick graphene-based electrodes

Carbon ◽

10.1016/j.carbon.2017.04.028 ◽

2017 ◽

Vol 119 ◽

pp. 257-266 ◽

Cited By ~ 48

Author(s):

Amir Azhari ◽

Ehsan Marzbanrad ◽

Dilara Yilman ◽

Ehsan Toyserkani ◽

Michael A. Pope

Keyword(s):

Additive Manufacturing ◽

3D Printing ◽

Powder Bed

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Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness

Metals ◽

10.3390/met11020266 ◽

2021 ◽

Vol 11 (2) ◽

pp. 266

Author(s):

Wakshum M. Tucho ◽

Vidar Hansen

Keyword(s):

Heat Treatment ◽

Solid Solution ◽

Additive Manufacturing ◽

Inconel 718 ◽

Solution Heat Treatment ◽

Hold Time ◽

Powder Bed Fusion ◽

Powder Bed ◽

Annealing Twins ◽

Complete Recrystallization

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. Despite this, the highest hardness obtained after aging for ST temperatures (970–1250 °C) is at 1100 °C/1 as we have ascertained in our previous studies. The unreleased residual stresses in the retained lattice defects potentially affect 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 hardness after aging or not. For this study, L-PBF-Inconel 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%. The high density of annealing twins evolved during 3 h of ST and only slightly varies for longer ST.

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Synergistic application of continuous granulation and selective laser sintering 3D printing for the development of pharmaceutical dosage forms with enhanced dissolution rates and physical properties

10.1101/2021.02.13.430988 ◽

2021 ◽

Cited By ~ 1

Author(s):

Rishi Thakkar ◽

Yu Zhang ◽

Jiaxiang Zhang ◽

Mohammed Maniruzzaman

Keyword(s):

Solid State ◽

3D Printing ◽

Physical Properties ◽

Dosage Forms ◽

Flow Properties ◽

Printing Process ◽

Powder Bed ◽

Printing Processes ◽

Binder Jetting ◽

Physical Mixtures

AbstractThis study demonstrated the first case of combining novel continuous granulation with powder-based pharmaceutical 3-dimensional (3D) printing processes to enhance the dissolution rate and physical properties of a poorly water-soluble drug. Powder bed fusion (PBF) and binder jetting 3D printing processes have gained much attention in pharmaceutical dosage form manufacturing in recent times. Although powder bed-based 3D printing platforms have been known to face printing and uniformity problems due to the inherent poor flow properties of the pharmaceutical physical mixtures (feedstock). Moreover, techniques such as binder jetting currently do not provide any solubility benefits to active pharmaceutical ingredients (APIs) with poor aqueous solubility (>40% of marketed drugs). For this study, a hot-melt extrusion-based versatile granulation process equipped with UV-Vis process analytical technology (PAT) tools for the in-line monitoring of critical quality attributes (i.e., solid-state) of indomethacin was developed. The collected granules with enhanced flow properties were mixed with vinylpyrrolidone-vinyl acetate copolymer and a conductive excipient for efficient sintering. These mixtures were further characterized for their bulk properties observing an excellent flow and later subjected to a PBF-3D printing process. The physical mixtures, processed granules, and printed tablets were characterized using conventional as well as advanced solid-state characterization. These characterizations revealed the amorphous nature of the drug in the processed granules and printed tablets. Further, the in vitro release testing of the tablets with produced granules as a reference standard depicted a notable solubility advantage (100% drug released in 5 minutes at >pH 6.8) over the pure drug and the physical mixture. Our developed system known as DosePlus combines innovative continuous granulation and PBF-3D printing process which can potentially improve the physical properties of the bulk drug and formulations in comparison to when used in isolation. This process can further find application in continuous manufacturing of granules and additive manufacturing of pharmaceuticals to produce dosage forms with excellent uniformity and solubility advantage.Abstract Figure

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Inconel 718 Microstructural Evolution Modeling During Sequential Forming Steps (Hot Forging Followed by Ring Rolling)

Proceedings of the 6th International Conference on Recrystallization and Grain Growth (ReX&GG 2016) ◽

10.1002/9781119328827.ch40 ◽

2016 ◽

pp. 271-277

Author(s):

&gtO. Beltran

Keyword(s):

Microstructural Evolution ◽

Inconel 718 ◽

Hot Forging ◽

Ring Rolling ◽

Evolution Modeling

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Effect of heat-treatment on microstructural evolution and mechanical behaviour of severely deformed Inconel 718

Materials Science and Engineering A ◽

10.1016/j.msea.2018.01.007 ◽

2018 ◽

Vol 715 ◽

pp. 295-306 ◽

Cited By ~ 10

Author(s):

Prabhat Chand Yadav ◽

Sandeep Sahu ◽

Anandh Subramaniam ◽

Shashank Shekhar

Keyword(s):

Heat Treatment ◽

Microstructural Evolution ◽

Mechanical Behaviour ◽

Inconel 718

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Mechanical properties of Inconel 718 additively manufactured by laser powder bed fusion after industrial high-temperature heat treatment

Journal of Manufacturing Processes ◽

10.1016/j.jmapro.2021.11.053 ◽

2022 ◽

Vol 73 ◽

pp. 642-659

Author(s):

Konrad Gruber ◽

Wojciech Stopyra ◽

Karol Kobiela ◽

Bartosz Madejski ◽

Maciej Malicki ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

High Temperature ◽

Inconel 718 ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Powder Bed ◽

High Temperature Heat Treatment ◽

Temperature Heat ◽

Temperature Heat Treatment

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On the manufacturability of Inconel 718 thin-walled honeycomb structures by laser powder bed fusion

Rapid Prototyping Journal ◽

10.1108/rpj-04-2021-0098 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

José M. Zea Pérez ◽

Jorge Corona-Castuera ◽

Carlos Poblano-Salas ◽

John Henao ◽

Arturo Hernández Hernández

Keyword(s):

Mechanical Properties ◽

Inconel 718 ◽

Dimensional Accuracy ◽

Honeycomb Lattice ◽

Lattice Structures ◽

Powder Bed Fusion ◽

Laser Powder Bed Fusion ◽

Content Type ◽

Powder Bed ◽

Thin Walled

Purpose The purpose of this paper is to study the effects of printing strategies and processing parameters on wall thickness, microhardness and compression strength of Inconel 718 superalloy thin-walled honeycomb lattice structures manufactured by laser powder bed fusion (L-PBF). Design/methodology/approach Two printing contour strategies were applied for producing thin-walled honeycomb lattice structures in which the laser power, contour path, scanning speed and beam offset were systematically modified. The specimens were analyzed by optical microscopy for dimensional accuracy. Vickers hardness and quasi-static uniaxial compression tests were performed on the specimens with the least difference between the design wall thickness and the as built one to evaluate their mechanical properties and compare them with the counterparts obtained by using standard print strategies. Findings The contour printing strategies and process parameters have a significant influence on reducing the fabrication time of thin-walled honeycomb lattice structures (up to 50%) and can lead to improve the manufacturability and dimensional accuracy. Also, an increase in the young modulus up to 0.8 times and improvement in the energy absorption up to 48% with respect to those produced by following a standard strategy was observed. Originality/value This study showed that printing contour strategies can be used for faster fabrication of thin-walled lattice honeycomb structures with similar mechanical properties than those obtained by using a default printing strategy.

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