Reducing cohesion of metal powders for additive manufacturing by nanoparticle dry-coating

Gärtner, Eric; Jung, Hyo Yun; Peter, Nicolas J.; Dehm, Gerhard; Jägle, Eric Aimé; Uhlenwinkel, Volker; Mädler, Lutz

doi:10.1016/j.powtec.2020.10.065

Cited by 34 publications

(21 citation statements)

References 49 publications

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“…Further, NP size distribution must be known to calculate the amount of NPs needed for an intended surface coverage level on the micro-powders [29]. It is known that the NP´s size influences the powder feedstock flowability [40,41] as attractive forces between micro-powders are reduced by roughening the surface with NPs [65,66]. However, a statistical investigation is still missing in the literature.…”

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

“…However, a statistical investigation is still missing in the literature. Following Gaertner et al [41], the feedstock's flowability behavior will be enhanced by optimum surface coverage level and optimum NPs size. As discussed in references [67,68], transmission electron microscope (TEM), dynamic light scattering (DLS), and analytical disc centrifugation (ADC) characterization techniques are recommended methods within an ILS to measure dry and colloidal NP size distributions.…”

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

“…As shown in Figure 3a, the surface coverage and the distribution of NPs on the micro-powder's surface can vary depending on the NP load and surface additivation technique. Additionally, NPs may be present as a dry powder [41] or in a colloidal solution [28,30]. These variations may affect powder feedstock material properties relevant for PBF-LB.…”

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

“…Detailed information on the comparison between TEM, DLS, and ADC can be found elsewhere [67,68], including the comparison of five analytical methods for particle diameter differentiation and bimodality identification [69]. Please note that the particle size can alter during the supporting process, mainly forced by agglomeration-induced effects [41]. Therefore, we advise determining both supported and colloidal NP size distribution.…”

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

“…The surface additivation of the metal and polymer powders can be performed by dry mixing or wet coating and subsequent or parallel drying [28,33,37,40,41]. The choice of coatingtechnique highly depend on the availability of NPs.…”

Section: Additivation Processmentioning

confidence: 99%

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Nanoparticle Additivation Effects on Laser Powder Bed Fusion of Metals and Polymers—A Theoretical Concept for an Inter-Laboratory Study Design All Along the Process Chain, Including Research Data Management

et al. 2021

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In recent years, the application field of laser powder bed fusion of metals and polymers extends through an increasing variability of powder compositions in the market. New powder formulations such as nanoparticle (NP) additivated powder feedstocks are available today. Interestingly, they behave differently along with the entire laser powder bed fusion (PBF-LB) process chain, from flowability over absorbance and microstructure formation to processability and final part properties. Recent studies show that supporting NPs on metal and polymer powder feedstocks enhances processability, avoids crack formation, refines grain size, increases functionality, and improves as-built part properties. Although several inter-laboratory studies (ILSs) on metal and polymer PBF-LB exist, they mainly focus on mechanical properties and primarily ignore nano-additivated feedstocks or standardized assessment of powder feedstock properties. However, those studies must obtain reliable data to validate each property metric’s repeatability and reproducibility limits related to the PBF-LB process chain. We herein propose the design of a large-scale ILS to quantify the effect of nanoparticle additivation on powder characteristics, process behavior, microstructure, and part properties in PBF-LB. Besides the work and sample flow to organize the ILS, the test methods to measure the NP-additivated metal and polymer powder feedstock properties and resulting part properties are defined. A research data management (RDM) plan is designed to extract scientific results from the vast amount of material, process, and part data. The RDM focuses not only on the repeatability and reproducibility of a metric but also on the FAIR principle to include findable, accessible, interoperable, and reusable data/meta-data in additive manufacturing. The proposed ILS design gives access to principal component analysis (PCA) to compute the correlations between the material–process–microstructure–part properties.

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Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

Section: Additivation Of Nps On As-produced Metal and Polymer Powder Feedstocksmentioning

confidence: 99%

Section: Additivation Processmentioning

confidence: 99%

See 3 more Smart Citations

Nanoparticle Additivation Effects on Laser Powder Bed Fusion of Metals and Polymers—A Theoretical Concept for an Inter-Laboratory Study Design All Along the Process Chain, Including Research Data Management

et al. 2021

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Laser-based powder bed fusion of Ti-6Al-4V powder modified with SiO2 nanoparticles

Emminghaus

Bernhard

Hermsdorf

et al. 2022

Int J Adv Manuf Technol

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In laser-based powder bed fusion of metals (PBF-LB/M), residual oxygen in the processing atmosphere is regarded as disruptive and disadvantageous for the manufacturing process and the resulting component properties. A novel approach to eliminate residual oxygen is to add small amounts of silane to the argon process gas. Silane eliminates residual oxygen and forms SiO2 nanoparticles, which in turn can be incorporated into the powder during the process. It is therefore necessary to evaluate the influence of these nanoparticles admixed to the metal powder. In this work, Ti-6Al-4V powder was modified with pyrogenic SiO2 nanoparticles generated by the reaction of a silane argon gas mixture with ambient air. Modified and unmodified powder was analyzed and processed using statistically designed experiments. An improvement of the flow rate according to DIN EN ISO 4490 (from 33.3 to 32.5 s/50 g) and increase of apparent density according to DIN EN ISO 3923 (from 2.52 to 2.58 g/cm3) could be observed after powder modification. No statistically significant effects of the modification on roughness, porosity, and hardness were found. The results demonstrate that powder modification using silane can lead to enhanced flowability without affecting the PBF-LB processing window of Ti-6Al-4V.

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Adapting Fe–Mn–Si–Cr shape memory alloy for laser powder bed fusion by adjusting the Mn content

Gärtner,

Meyenborg,

Toenjes

2023

Prog Addit Manuf

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Shape memory alloys (SMA) are functional materials exhibiting the shape memory effect. Conventional standard manufacturing technologies for shape memory alloys include melting, casting, and forming. These often require additional machining steps to achieve the final component shape, limiting the geometric design. The production of SMAs using additive manufacturing technologies opens up new possibilities, but research has been limited, especially for iron-based SMAs. The present study investigated whether an iron-based SMA alloy powder suitable for the additive manufacturing process can be produced via atomization and subsequently 3D printed with laser powder bed fusion (PBF-LB/M). Two FeMnSi SMAs with varying manganese contents of 23.6% and 28.5% were successfully atomized and laser processed. The effect of the manganese content on the shape memory characteristics was investigated by means of dilatometry. A 5 wt% change in manganese content was found to impact the onset of the keyhole fusion mode for PBF-LB/M as well as the resulting shape memory characteristics. Reduced manganese content is shown to enhance the shape memory effect of FeMnSi.

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Reducing cohesion of metal powders for additive manufacturing by nanoparticle dry-coating

Cited by 34 publications

References 49 publications

Nanoparticle Additivation Effects on Laser Powder Bed Fusion of Metals and Polymers—A Theoretical Concept for an Inter-Laboratory Study Design All Along the Process Chain, Including Research Data Management

Nanoparticle Additivation Effects on Laser Powder Bed Fusion of Metals and Polymers—A Theoretical Concept for an Inter-Laboratory Study Design All Along the Process Chain, Including Research Data Management

Laser-based powder bed fusion of Ti-6Al-4V powder modified with SiO2 nanoparticles

Adapting Fe–Mn–Si–Cr shape memory alloy for laser powder bed fusion by adjusting the Mn content

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