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Authors:

Naiara Azurmendi (TECNALIA, Basque Research and Technology Alliance (BRTA), Spain), Iñigo Agote (TECNALIA, Basque Research and Technology Alliance (BRTA), Spain), Cristina Fernandes (PALBIT S.A., Portugal), Daniel Figueiredo (PALBIT S.A., Portugal)

Abstract:

Additive manufacturing of hardmetals is gaining attention due to the possibility of fabricating complex shaped parts and new functional designs. Comparing to laser-based AM processes, binder jetting appears to be more promising technology due to its low-cost, fast manufacturing process that produces stress and crack-free parts with isotropic properties. In the present work, properties of two different plasma spherodized commercial powders (AMWC701 and AMWC702 grades), have been characterized and printed with binder jetting technology. In addition, final properties of the printed parts sintered in a Sinter-HIP furnace at two different temperatures (1455°C and 1480°C) have been evaluated. Density, shrinkages, microstructure and hardness have been analysed. Best results were obtained with AMWC702 grade sintered at 1455°C, where near full density was obtained (>99%). Measured Vickers hardness was 1227 HV30, which is coherent with the microstructural analysis and close to medium grained commercial products.

DOI:

https://doi.org/10.59499/WP225371945

Authors:

Georg Poehle (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Germany), Antje Schauer (Technische Universität Dresden, Germany), Jakob Scheibler (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Germany), Thomas Weissgaerber (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Germany), Peggy Barthel (Technische Universität Dresden, Germany), Anita Maennel (Technische Universität Dresden, Germany), Volker Adams (Technische Universität Dresden, Germany), Axel Linke (Technische Universität Dresden, Germany), Peter Quadbeck (Offenburg University of Applied Sciences, Germany)

Abstract:

Biodegradable metals have entered the implant market in recent years, but still do not show fully satisfactory degradation behaviour and mechanical properties. In contrast, it has been shown that pure molybdenum has an excellent combination of the required properties in this respect. We report on PM based screen printing of thin-walled molybdenum tubes as a processing step for medical stent manufacture. We also present data on the in vivo degradation and biocompatibility of molybdenum. The degradation of molybdenum wires implanted in the aorta of rats was evaluated by SEM and EDX. Biocompatibility was assessed by histological investigation of organs and analysis of molybdenum levels in tissue extracts and body fluids. Degradation rates of up to 13.5 µm|y were observed after 12 months. No histological changes or elevated molybdenum levels in organ tissues were observed. In summary, the results further underline that molybdenum is a highly promising biodegradable metallic material.

DOI:

https://doi.org/10.59499/WP225371879

Authors:

Johannes Trapp (Fraunhofer IFAM, Germany), Thomas Schubert (Fraunhofer IFAM, Germany), Dumitru Mitrica (National Research & Development Institute for Non-ferrous and Rare Metals, Romania), Ioana Anasiei (National Research & Development Institute for Non-ferrous and Rare Metals, Romania), Thomas Weißgärber (Fraunhofer IFAM, Germany)

Abstract:

Aluminum-based metal-matrix-composites (AMCs) show attractive properties to meet the growing demand for lightweight construction for example in the automotive and aerospace industries. Limiting factors are difficulties in processing and machining as well as comparably low operating temperatures. The first issue is addressed using spark plasma sintering (SPS) to produce fully dense net-shape compacts. Therefore, the electrical properties of the powders must be understood and adjusted. To increase operation temperature, alloys with thermally more stable Al3Fe dispersoids, certain intermetallic phases, or complex constitutional alloys have been investigated. The latter are developed with the help of a systematic selection process to calculate the thermodynamic and kinetic criteria to predict the phases formed. Those AMCs show melting temperatures above 1000 °C while keeping the density below 4,5 g|cm³. Aiming for compressive strength > 800 MPa and elongation to fraction >1 % makes the materials suitable e.g. for front wheel brake disc applications.

DOI:

https://doi.org/10.59499/WP225371604

Authors:

Eshwara Nidadavolu (Helmholtz-Zentrum Hereon, Germany) Martin Mikulics (ERC-2, Forschungszentrum Jülich, Germany) Martin Wolff (Helmholtz-Zentrum Hereon, Germany) Thomas Ebel (Helmholtz-Zentrum Hereon, Germany) Regine Willumeit-Römer (Helmholtz-Zentrum Hereon, Germany) Berit Zeller-Plumhoff (Helmholtz-Zentrum Hereon, Germany) Joachim Mayer (ERC-2, Forschungszentrum Jülich, Germany) Hilde Helen Hardtdegen (ERC-2, Forschungszentrum Jülich, Germany)

Abstract:

Carbon (C) residuals at specific microstructural features are detected in a correlative way in the metal injection molded (MIM) Mg-0.6Ca material. Micro Raman mappings revealed Raman modes at nearly 1370 cm-1 and 1560 cm-1 that can be ascribed to elemental C, and C-C stretching at 1865 cm-1. The MIM Mg feedstock contained PPcoPE based backbone polymer that dissociates during thermal debinding (380 °C - 550 °C) prior to argon atmosphere sintering (644 °C). The decomposition of MgC2 and Mg2C3 carbides at 450 °C and 600 °C respectively, releases free C that can be trapped in the Mg matrix. The presence of calcium (Ca) leads to the formation of CaC2 phases during sintering that retains in the microstructure. Energy dispersive x-ray (EDX) analysis revealed the SiO2 impurities adjacent to the C, Ca and oxide detections. These findings can provide insights about the cell adhesion characteristics of PM Mg materials.

DOI:

https://doi.org/10.59499/EP256763349

Authors:

Arnaud Leclef (1,2), Alexandre Mégret (1), Véronique Vitry (1), Arnaud Tricoteaux (2)

1- Metallurgy Unit, Faculty of Engineering, University of Mons, Belgium.

2- Céramaths, UPHF, France

Abstract:

The use of cobalt as binder for tungsten carbide raises more and more questions of environmental, health and societal ethics. The aim of this study is to find alternatives to cobalt as a binder for tungsten carbide. The binders investigated for this study were FeMn-based binders. The latter were carbon-doped to prevent the presence of eta-phase. Expected results required HV30 > 1600, and fracture toughness > 10 MPa·m1/2. The first aspect is to model the phases that were generated by the replacement of cobalt. Pseudo-binary phase diagrams have been performed. The second aspect was to process the alternative "WC – promising alternative binder" composites. The powder metallurgy method was chosen for this purpose. Vacuum sintering technology was used. The samples were then mechanically and morphologically characterized.

DOI:

https://doi.org/10.59499/EP246278247

Authors:

E. Carreño-Morelli (1),L. Meylan (1), M. Rodriguez-Arbaizar (1), R. Constantin (2), M. Stucki (3), G. Wälder (3)

1- HES-SO Valais-Wallis, University of Applied Sciences and Arts Western Switzerland, CH-1950 Sion.

2- HES-SO He-ARC, University of Applied Sciences and Arts Western Switzerland, CH-2400 Le Locle

3- HES-SO HEPIA, University of Applied Sciences and Arts Western Switzerland, CH-1202 Geneva

Abstract:

Ti(C,N)-MoNi cermets cutting tool inserts have been produced by cold compaction and sintering of commercial ready to press granules. The inserts have been characterized by hardness, density measurements and SEM observations. The cutting edges of sintered inserts were sharpened by laser grinding before coating with a PVD nitride layer by High power impulse magnetron sputtering. Instrumented scratch tests were conducted to evaluate the coating adhesion on both reference cemented carbide and experimental cermet inserts.

DOI:

https://doi.org/10.59499/EP235763911

Authors:

Alejo Avello (1,2), Ernesto Urionabarrenetxea (1,2), José Manuel Martín (1,2)

1- CEIT-Basque Research and Technology Alliance (BRTA), Donostia- San Sebastián, Spain

2- Universidad de Navarra, Tecnun, Donostia-San Sebastián, Spain.

Abstract:

Prediction of particle size distribution (PSD) in close-coupled gas atomization is of great interest to optimize nozzle designs and to accelerate the choice of optimum operational variables in first-time atomizations. Previous works have shown that CFD simulations based on simplifying assumptions can correctly predict trends of median particle size of copper powders produced at different nitrogen pressures. In this work, a refinement of the simulation procedure developed by the authors is pre-sented. Particle breakup is computed from a Discrete Phase Model (DPM), with injection input data calculated from an Eulerian model. The new model is used to compare, for the first time, simulated and experimental results of three different pairs metal-gas: copper with nitrogen, copper with argon and tin with nitrogen. Even for materials with such disparate melting points, the simulations predict quite accurately the median particle size for varying gas-to-metal mass flow rate ratios.

DOI:

https://doi.org/10.59499/EP246282819

Authors:

Zhenghua Yan (Simtec Soft Sweden AB, Sweden) Yan Liu (Simtec Soft Sweden AB, Sweden)

Abstract:

Metal Binder Jetting is a versatile 3D printing technology requiring post-processing to enhance green parts' mechanical properties, with debinding being a critical yet complex stage. This study employs Computational Fluid Dynamics (CFD) simulations to address debinding challenges, focusing on chemical reactions, gas flow, and heat transfer within porous samples.A robust model simulates debinding using polyvinyl alcohol as the organic binder. The reaction produces CO2, H2O, and C2H6O, accounting for transient temperature variations, moisture content, and heat transfer through conduction, convection, and radiation. Results demonstrate how debinding progresses from the outer layer to the core, influencing bulk density and binder removal. Detailed distributions of gas species, velocity, and pressure provide valuable insights into optimizing debinding cycles, preventing defects, and understanding atmospheric conditions.This comprehensive CFD approach demonstrates its capability to handle coupled multi-physics processes, paving the way for enhanced efficiency and product quality in MBJ post-processing for complex porous structures.

DOI:

https://doi.org/10.59499/EP256717663

Authors:

Sebastian Riecker (Fraunhofer IFAM, Dresden Branch, Germany) Jonas Bonk (Fraunhofer IFAM, Dresden Branch, Germany) Caroline Wierling (Fraunhofer IFAM, Dresden Branch, Germany) Thomas Studnitzky (Fraunhofer IFAM, Dresden Branch, Germany) Robert Teuber (Fraunhofer IFAM, Dresden Branch, Germany) Thomas Weißgärber (Fraunhofer IFAM, Dresden Branch, Germany)

Abstract:

There is an increasing interest in the additive manufacturing (AM) production of light metal alloys such as titanium or aluminum alloys. Due to their good mechanical performance combined with low density, these alloys are in high demand in various industries, such as in the mobility sector. Compared to powder bed AM processes, slurry-based processes have the advantage that no dry, potentially flammable powder has to be handled. Furthermore, even irregular powder with poor flowability can be processed into homogeneously packed green parts. However, challenges arise in connection with reactive powders that are oxygen-affine: Potential reactions between the powder and the suspension medium, as well as the complete removal of the organic components during thermal debinding, pose challenges. This paper evaluates the production of Ti-6Al-4V and Al6061 sinter parts using the gel casting process and presents results regarding the material properties achieved and the current state of development.

DOI:

https://doi.org/10.59499/EP256767411

Authors:

Dominik Schmid (1) ; Paul Prichard (2)

1- Kennametal Shared Services GmbH, Germany

2- Kennametal Inc., United States of America

Abstract:

Additive manufacturing provides new opportunities for cutting tools, enabling geometric freedom to enhance functionality and performance. The challenge in realizing the full potential is multifarious: additive manufacturing needs to match the material quality of existing processes while creating these complex geometries. At the same time the engineered tool designs have to make use of the geometric freedom to exceed the capabilities of conventional tools. This work will highlight some challenges and solutions in processing cemented tungsten carbide as well as hot work tool steel. The presentation will also discuss opportunities with respect to tool design and show examples of innovative structures.

DOI:

https://doi.org/10.59499/EP235763604

Authors:

Axel Müller-Köhn (Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Germany), David Werner (Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Germany), Tamara Aleksandrov Fabijanić (University of Zagreb, Croatia), Ivan Jeren (Alfa Tim d.o.o., Croatia)

Abstract:

Water and cellulose-ether-based extrusion of hardmetals give the opportunity of an environmentally friendly processing. Furthermore, water as a solvent significantly reduces the demands in occupational safety and also costs in suction systems and drying processes.Use of water requires specific binders and additives to achieve the desired processing behavior of extrusion feedstocks as well as the necessary hardmetal properties after sintering. Additionally, water removal during drying of extruded parts demands well controlled conditions to ensure shape retention and defect free green parts.In this presentation necessary organics and processes for a successful feedstock preparation and extrusion will be shown. As an example, it was possible to apply submicron (d50 < 1 µm) WC-10 Co and binder free, nano scaled WC powders. Finally, resulting material properties of extruded and sintered parts will be demonstrated.

DOI:

https://doi.org/10.59499/WP225371900

Authors:

Kazi Sofia (1), Leach Lindsay (2), Hryha Eduard (1)

1- Chalmers University of Technology, Gothenburg, Sweden

2- Alfa Laval Technologies AB, Eskilstuna, Sweden

Abstract:

Powder degradation during additive manufacturing poses a significant challenge for achieving optimal part quality as well as maximal powder feedstock utilization and hence economy and sustainability of the process. Stainless steel 316L is a widely utilized material in powder bed fusion – laser beam (PBF-LB) due to its excellent processability, good corrosion resistance and mechanical properties of the PBF-LB processed components. This study investigates the influence of 316L powder properties and powder reuse on the powder surface oxide chemistry and hence processability by PBF-LB. Changes in powder surface chemistry were studied by HR SEM and X-ray Photoelectron Spectroscopy in virgin and reused state. Results indicate that there is evident degradation in powder properties during powder re-use with increase in oxygen content in the powder, connected to increase in thickness of iron-base surface oxide layer as well as fraction of Cr-rich particulate oxide phases.

DOI:

https://doi.org/10.59499/EP246282011