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Authors:

S.A. Razavi (1,2), M. Morales (1,2), I. Serrano (2,3), L. Llanes (1,2), J. Llorca (2,3), G. Fargas (1,2)

1- CIEFMA-Department of Materials Science, Universitat Politècnica de Catalunya, Barcelona-Tech, Spain.

2- Centre for Research in Multiscale Engineering of Barcelona, Universitat Politècnica de Catalunya, Barcelona-Tech, Spain.

3- Institute of Energy Technologies and Department of Chemical Engineering, Universitat Politècnica de Catalunya, Barcelona-Tech, Spain.

Abstract:

Direct Ink Writing (DIW) is an innovative technique for fabricating complex ceramic catalysts with several advantages compared with traditional catalysts. However, these catalysts still face challenges in achieving adequate catalytic performance and structural integrity. This study focuses on DIW-fabricated 3mol% yttria-stabilized zirconia (3YSZ) monoliths coated with a cobalt-3YSZ catalytic functional layer. After the sintering process, the monoliths were coated by the dip-coating technique, using inks based on cobalt (II) acetate tetrahydrate and 3YSZ, and re-sintered. The microstructure of coated monoliths was characterized by field emission scanning electron microscopy equipped with an EDX detector and Raman spectroscopy. Finally, the catalytic performance of monoliths was investigated by conducting the Ethanol Steam Reforming (ESR) reaction. Results show that the dip-coating process uniformly coated the monoliths. The coated monolith significantly enhanced catalytic performance and reduced the temperature of the complete ethanol conversion compared with the uncoated one.

DOI:

https://doi.org/10.59499/EP246280837

Authors:

Marta Ceroni (Politecnico di Torino, Italy), Lorenza Maddalena (Politecnico di Torino, Italy), Marco Actis Grande (Politecnico di Torino, Italy)

Abstract:

Cu powders show high reflectivity when exposed to a laser having wavelengths in the range of 1064-1080 nm, hindering the processability when manufacturing by red-light laser powder bed fusion. Green or blue lasers help overcoming this issue, as well as the change of the chemical composition of the powder. However, other approaches may also be used. The present paper analyses the effect of coatings applied on elemental Cu-powders on the absorbance of the resulting material. Different amounts of Graphite Oxide have been deposited on the surface of metal powders by a nanocoating approach. The prepared powders have been characterized evaluating the absorbance in the red, green, and blue light wavelengths using UV-Vis spectroscopy. The uniformity of GO coating was also evaluated by scanning electron microscopy and Raman spectroscopy.

DOI:

https://doi.org/10.59499/WP225372154

Authors:

Miroslav Karlík (CTU Prague, Czech Republic) Hana Thürlova (University of Chemistry and Technology, Czech Republic) Filip Průša (University of Chemistry and Technology, Czech Republic) Jaroslav Cech (CTU Prague, Czech Republic) Petr Hausild (CTU Prague, Czech Republic)

Abstract:

CoCrFeNiMn alloy in equiatomic composition was prepared from pure metals by powder metallurgy, and the reinforcing carbides were formed in situ after adding 1 wt.% of two precursors – machined graphite (C) and plasma-gasified carbon (PG). The powder was either mixed with the precursors, or 30 min. of mechanical alloying (MA) in a planetary ball mill was carried out. The microstructure, phase composition, and mechanical properties of spark plasma sintered (SPS) compacts were studied. During sintering, the matrix remained as an FCC phase while Cr23C6 carbides, which formed throughout MA, transformed to Cr7C3. The best mechanical properties were achieved for the PG-reinforced alloy after 30 min of MA. This material reached a compressive yield strength (CYS) of 1237 ± 50 MPa and ultimate compressive strength (UCS) of 1998 ± 46 MPa, together with ductility of 25%. The MA+SPS reference alloy compacts without carbide reinforcement had CYS of 988 ± 14 MPa; the UCS was not measured because of the very high plasticity of the alloy (no fracture occurred).

DOI:

https://doi.org/10.59499/EP256764300

Authors:

Silvia Baselli (University of Trento, Italy), Alberto Molinari (University of Trento, Italy)

Abstract:

The thermodynamic driving force of sintering is the decrease of the Gibbs free energy related to the excess of specific surface area of the powder. Nevertheless, for cold compacted green parts, the mass transport mechanisms which allow atoms to move to form the neck are promoted by the deformation in compaction that acts as a mechanical driving force expressed through the geometrical and structural activity. The powder particles are in contact over a surface, condition that affects the geometrical relationships in the neck region. The material is strain hardened, the concentration of structural defects is higher than that in the starting powder (enhanced diffusivity). The effect on sintering shrinkage of the geometrical activity has been explained in previous works and a theoretical model is available. To highlight how structural activity acts, a dilatometry study has been carried out on ferrous materials (plain iron and AISI 316L) and different powder morphology.

DOI:

https://doi.org/10.59499/WP225372160

Authors:

Mark Taylor (MTC, United Kingdom) Ryan Pitchford (MTC, United Kingdom) Kieran Bullivant (MTC, United Kingdom)

Abstract:

The use of cold spray additive manufacturing (CSAM) for large format component manufacture relies on powder suitability and the heat treatment post-processing to achieve the required properties.This study assessed the impact on performance of incorporating recycled non-deposited powder into virgin powder. A benchmark study was conducted, where the mechanical properties of samples produced by CASM using virgin and recycled feedstocks were compared.Recycled powder was tested for suitability for CSAM. Virgin powder was mixed with various proportions of recycled powder and used to manufacture test samples that were subsequently heat treated and mechanical tested, with performance compared against the 100% virgin material benchmark.Initial results showed that morphology of the recycled powder has a large impact on the volume that can be introduced.

DOI:

https://doi.org/10.59499/EP256767945

Authors:

Reinhard Steinhilber (1); Christian Staudigel (1); Christian Fischer (1)

1- Headmade Materials GmbH, Germany

Abstract:

Headmade Materials pushes the Powder Metallurgy further into the Metal AM market with its sinter-based AM-technology called ColdMetalFusion. Furthermore, Headmade Materials partners with industry leaders in the ColdMetalFusion Alliance to leverage the potential of reliable serial production in Metal AM. Since the ColdMetalFusion process runs on standard machines of AM and PM, the robustness and reliability of the process is unmatched and is proven by investigations on dimensional accuracy and reproducibility in this study. Multiple jobs with the same part arrangement were built and characterised. The test bars were aligned in X-, Y-, and Z-direction over the whole build volume. Outstanding results were achieved due to the combination of mature SLS technology and low, homogeneous shrinkage in all three dimensions during sintering.

DOI:

https://doi.org/10.59499/EP235762586

Authors:

Mihai Iovea (Accent PRO 2000 s.r.l., Romania), Gabriela Mateiasi (Accent PRO 2000 s.r.l., Romania), Marian Neagu (Accent PRO 2000 s.r.l., Romania), Alexandru Enciu (Accent PRO 2000 s.r.l., Romania), Andrei Stanciulescu (Accent PRO 2000 s.r.l., Romania), Mihaela Poterasu (Accent PRO 2000 s.r.l., Romania), Monica Mirea (Accent PRO 2000 s.r.l., Romania)

Abstract:

We present our X-ray high-resolution sintered and additive manufactured parts in-line NDT investigations based on various mini|microfocus X-ray set-ups. We are introducing also our latest development, an industrial combined X-ray scanner and a Laser-based 3D profiler machine for sintered parts in-line NDT control in one short pass. With the new equipment design we combined two advanced control techniques: the Laser-based profiler for getting the parts 3D shape measurement with 2-3% accuracy, followed by an X-ray digital imaging system for parts internal defects identification, based on a minifocus X-rays source and a TDI (Time Delayed Integration) X-ray detector. The system is able to compute also the sample' local density for sintered ceramic ballistic plates and to NDT analyse the transmission digital Xray images at a pixel size of 60 microns for detecting the internal defects.

DOI:

https://doi.org/10.59499/WP225370755

Authors:

Magnusson Anders (1), Shipley James (1), Gårdstam Johannes (1)

1- Quintus Technologies AB, Västerås, Sweden

Abstract:

Additive Manufacturing (AM) technology naturally benefits from Hot Isostatic Pressing (HIP) post-processing to enhance reliability and mechanical properties for components in high-risk, mission-critical applications. Over recent years, investigations have explored combining AM and HIP to reduce manufacturing time and costs and improve mechanical properties of AM builds, utilizing innovative concepts such as speed, shell, and Lack of Fusion (LoF) printing coupled with final densification using HIP. This paper gives an initial compilation and highlights the potential benefits and pitfalls of these innovative strategies for high-volume AM manufacturing of high-performance components from various metal alloys.

DOI:

https://doi.org/10.59499/EP246219721

Authors:

Nathan Liebgott (IRT-M2P, France) Baraa Qaddah (IRT M2P, France) Meher Zaied (IRT M2P, France) Raphael Durand (IRT M2P, France) Benjamin Luiset (Metalor, France) Victor Cribier (Metalor, France)

Abstract:

The demand for high-performance powders from precious metals is growing in the electrical connector market, where superior conductivity and reliability are essential. This study investigates the comparative efficiency of Electrode Induction Melting Gas Atomization (EIGA) and Vacuum Induction Melting Gas Atomization (VIGA) in producing precious metal powders tailored for this application. Key powder characteristics, including particle size distribution, morphology, flowability, cohesive angle, and oxygen, nitrogen, and hydrogen content, are analyzed.Results show that VIGA powders contain smaller particles whereas powders obtained by the EIGA are rounder and more spherical. Furthermore, the VIGA powders shows better static as well as dynamic cohesiveness than EIGA powders. These powders were compared to the precious metal powders obtained by water atomization to evaluate their cohesion regarding morphology and particle size distribution. The static cohesion index of powders produced by VIGA and EIGA is four times lower than that of powders obtained through water atomization.

DOI:

https://doi.org/10.59499/EP256766697

Authors:

Alexander Medina Peschiutta (1,2), Marvin Just (1,2), Ralph Useldinger (2), Jörg Baller (1)

1- Department of Physics and Materials Science, University of Luxembourg, 162A Avenue de la Faiencerie, L-1511 Luxembourg, Grand Duchy of Luxembourg

2- CERATIZIT Luxembourg S.à r.l., 101 Route de Holzem, L-8232, Grand Duchy of Luxembourg

Abstract:

We present a comparative study on determining the critical binder volume concentration (CBVC) of a hard metal paste using the following techniques: theoretical calculation, density method, oil titration, binder titration, and Reddy's model. The theoretical calculations involve density measurements to discern the carbide powder-free volume. The titration methods consist of a stepwise increase of the organic content while the mixer torque is recorded. In contrast, Reddy's model requires the preparation of several feedstocks at varying solid loadings, which are tested in a capillary rheometer to obtain the CBVC. The paste consists mainly of nano-sized tungsten carbide-cobalt (powder phase) and a macromolecular multiphase system (organic phase). The accuracy and expenditure of experimental work of the different methods are discussed.

DOI:

https://doi.org/10.59499/EP235764669

Authors:

Joni Reijonen (1); Juan Silva (1); Oskar Pulli (2); Kasper Hahtonen (2); Jari Ulkuniemi (2); Jari Niskanen (2); Pasi Puukko (1); Sini Metsä-Kortelainen (1)

1- VTT Technical Research Centre of Finland Ltd., Finland

2- University of Oulu, Finland

Abstract:

Additive manufacturing is often referred to as resource-efficient or even sustainable manufacturing with very little reliable scientific data to support the claims. Here we have made a comparative life cycle inventory of the energy and raw material flows during PBF-LB AM and CNC machining of three components having different geometrical features and functionalities: gear, impeller and manifold. The scope of this study was on the manufacturing phase of the components (from gate-to-gate). The energy and material consumptions were measured, with emphasis on providing accurate, transparent and reliable data of the most important input flows through direct measurement. For all the three studied components, PBF-LB consumed more energy, but required less material, than CNC machining. Geometry of the component had the most significant impact on the energy and material consumption in these processes. Optimizing part geometry and process parameters in PBF-LB to minimize resource consumption showed much potential for improvement.

DOI:

https://doi.org/10.59499/EP235761105

Authors:

Hossein Rajaei (1), Alberto Molinari (1), Iñigo Agote (2), Miguel Ángel Lagos (2), Daniele Ferrari (3), Marta Dai Pré (4)

1- Department of Industrial Engineering, University of Trento, Italy

2- TECNALIA, Basque Research and Technology Alliance (BRTA), Spain

3- DELLAS SPA, Italy

1- Plumake, Italy

Abstract:

This study explores the effectiveness of Field Assisted Sintering Technology (FAST) in producing cutting tools using a Bronze 90/10, Co, Fe, and W powder mix in granulated and non-granulated conditions. The goal is to evaluate and demonstrate FAST efficiency by comparing results obtained on the same system using a conventional sintering approach. For the characterization of the samples, a Rietveld refinement XRD patterns combined with microstructural analysis, based on SEM and EDXS, was considered. The study revealed that the sintering process significantly influenced microstructural characteristics. The FAST process, known for rapid heating and short sintering periods, maintained a consistent ratio of starting phases, unlike conventional sintering prone to reactions, diffusion, and intermetallic compound formation. Conventional sintering resulted in cobalt polymorphs also exhibited a lattice expansion with respect to the starting powder, resulting mainly from the atomic rearrangement during prolonged sintering process. FAST samples showed a lower volume change, due to short sintering time.

DOI:

https://doi.org/10.59499/EP246281338