Individual Papers

Authors:

Mohammad Momeni (1), Lluis Gimeno-Fabra (1), Herbert Danninger (2), Christian Gierl-Mayer (2)

1- European Patent Office, Patentlaan 2, 2288 EE Rijswijk, Netherlands

2- Institute of Chemical Technologies and Analytics, Technische Universität Wien, Getreidemarkt 9/164-03, A-1060 Wien/Vienna, Austria

Abstract:

Patents provide a solid legal framework for inventors to fairly benefit from their contribution to technology. The social deal around patents, requires a clear and sufficient disclosure of novel and inventive subject-matter. This means that patents contain valuable information on the most advanced state of innovation worldwide. Consequently, providing an overview of the granted patents seems to be crucial to know the industrial trends. In this presentation, the public data is decoded and presented in selected granted patents at European Patent Office (EPO) from 2015 to 2020 (for which the opposition periods have expired) to sketch this evolution and show the major industrial trends. The scope of the presentation is revealing some latest industrial developments and growing technology developments in manufacturing of ferrous powders & sintered steels.

DOI:

https://doi.org/10.59499/EP235762617

Authors:

Martin Bram (Forschungszentrum Jülich, Germany), Jesus Gonzalez-Julian (RWTH Aachen University, Germany), Jan W. Coenen (Forschungszentrum Jülich, Germany), Andrey Litnovsky (Forschungszentrum Jülich, Germany)

Abstract:

In future fusion power plants, plasma-facing materials for the first wall of the reactor have to withstand extreme conditions combining long-term stability during regular operation and suppressed oxidation in the case of an accident. Self-passivating metal alloys with reduced thermo-oxidation (SMART) are promising candidates. Based on tungsten as matrix material, the alloys contain chromium as passivating element and yttrium as active element. Recently, it has been shown that submicron grain sizes led to the best oxidation resistance. Processing of such kind of materials is challenging. Here, field assisted sintering technology|spark plasma sintering (FAST|SPS) of mechanically alloyed tungsten, chromium and yttrium powders was applied to produce submicron grained SMART materials with homogeneous microstructure and well-balanced properties. Main factors influencing the processing of SMART materials via FAST|SPS are discussed and first attempts to scale up the technology (100 x 100 mm2) are presented. Finally, oxidation resistance under accident conditions was investigated.

DOI:

https://doi.org/10.59499/WP225371906

Authors:

C. Kukla (1); V. Momeni (2); G. Poehle (3); S. Riecker (3); S. Schuschnigg (2)

1- Montanuniversitaet Leoben, Industrial Liaison Department, Leoben, Austria

2- Montanuniversitaet Leoben, Department of Polymer Engineering and Science, Institute of Polymer Processing, Leoben, Austria

3- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Dresden, Germany

Abstract:

Material Extrusion with filaments, Fused Filament Fabrication – FFF, is the most widespread additive manufacturing technology. This counts mainly for polymers, since the use of this technology for metal and ceramic powders is still in its early days. For several metals, filaments can be bought in the market. Aluminium has a low sintering temperature already in the range of the temperatures for thermal debinding of many feedstocks and needs special sintering regimes. To meet these special requirements, a feedstock for the production of highly filled aluminium filaments was developed. The printed parts are debinded by solvents. Here, the following results are presented: 1) rheological behaviour of the feedstock, 2) debinding behaviour with emphasis on the selection of solvents and 3) printing performance.

DOI:

https://doi.org/10.59499/EP235763812

Authors:

Juan Alfonso Naranjo (UCLM, Spain), Cristina Berges (UCLM, Spain), Javier Hidalgo (UCLM, Spain), Gemma Herranz (UCLM, Spain)

Abstract:

Fused filament fabrication is emerging as a promising sinter-based technology rivalling widespread beam-based approaches for the production of metal components. In the first step, a filament composed of a polymeric matrix with a high powder loading is extruded by a capillary die and deposited layer by layer to produce the desired geometry. Filament properties are critical for the printing performance, still, there is not a consensus on the range of filament properties adequate for printing. This work aims to establish threshold values for filament features leading to satisfactory printing by analysing the rheology and mechanical properties of filaments made of powders of diverse ferrous alloys. It is concluded that besides other consequences, filament rheology and mechanical properties have a strong impact on the shear stresses developed during printing, which limit the printing speed. These parameters can be engineered by solid loading and temperature to maximize the printing process.

DOI:

https://doi.org/10.59499/WP225372277

Authors:

Marco Zago (University of Trento, Italy), Alex Rambelli (Sacmi Imola s.c., Italy), Ilaria Cristofolini (University of Trento, Italy)

Abstract:

The influence of compaction strategy on compressibility and densification of metal powders has been extensively studied in previous work; effective compaction mechanics relationships and a densification model have been derived on experimental basis. Nevertheless, such studies also highlighted the need for further investigation concerning filling step, playing major role in obtaining high density, homogeneously distributed. This work focuses on filling step, considering the influence of both geometry, and filling strategy. Ring shaped parts with different height to thickness ratios (H|T) have been produced, also varying filling parameters as filling shoe speed, suction speed, and number of shakes of the filling shoe. Filling density was derived, as a function of above parameters, also highlighting the most critical parameters affecting filling density. Moreover, green density was measured in different points, referring to filling shoe movement, aiming at identifying the effect of filling strategy on flatness and parallelism of planes resulting from compaction.

DOI:

https://doi.org/10.59499/WP225368618

Authors:

Marion Coffigniez (UCLouvain, Institute of Mechanics Materials and Civil Engineering, IMAP, Belgium), Amandine Duchaussoy (UCLouvain, Institute of Mechanics Materials and Civil Engineering, IMAP, Belgium), Matthieu Marteleur (UCLouvain, Institute of Mechanics Materials and Civil Engineering, IMAP, Belgium), Justine Papillon (Univ Lyon, INSA Lyon, UCBL, CNRS, MATEIS, UMR 5510, France), Eric Maire (Univ Lyon, INSA Lyon, UCBL, CNRS, MATEIS, UMR 5510, France), Pascal Jacques (UCLouvain, Institute of Mechanics Materials and Civil Engineering, IMAP, Belgium)

Abstract:

ß-metastable Ti alloys exhibit a very large work hardening rate together with an outstanding resistance to damage nucleation, bringing a very high ductility. Such a behavior could enable to counteract the decrease of mechanical properties caused by solidification cracking|hot tearing, balling or porosity formation during laser powder bed fusion. The binary Ti-12 wt.% Mo grade was chosen as a case study, using powder mixture as a first approach. As-printed microstructures highlight the formation of structures related to the solidification scheme, as well as specific Mo solute partitioning depending on the printing parameters. Such a specific microstructure brings a large increase of the tensile strength compare to the cast reference. Furthermore, when the chemical homogenisation obtained is large enough to reach 95 % of ß-metastable microstructure, ductility comparable to the cast reference is reached after a simple flash heat treatment, as well as an outstanding low sensitivity to defects.

DOI:

https://doi.org/10.59499/WP225371687

Authors:

Martin Bram (1), Fernando Maccari (2), Monica Keszler (1), Tarini Prasad Mishra (1)

1- Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung, 52425 Jülich, Germany

2- Technical University of Darmstadt, Institute for Materials Science, Functional Materials, 64287 Darmstadt, Germany

Abstract:

Flash spark plasma sintering (Flash SPS) is an attractive alternative method for the processing of Nd-Fe-B magnets with anisotropic magnetic properties. Therefore, a load is applied on a pre-compacted sample. Then, a well-defined power pulse is applied followed by deformation and densification of the sample in seconds. Compared to established processing of anisotropic magnets via hot pressing with subsequent die-upsetting, Flash SPS introduces the possibility of electroplasticity as an additional deformation mechanism. This mechanism has the potential to improve the magnetic properties through the fine-tuning of the microstructure. Our results reveal that suitable pre-heating of the sample before applying the power pulse plays a crucial role for tailoring grain size and grain aspect ratio, both being the key for well-pronounced anisotropic magnetic properties. For better understanding of the relationship between Flash SPS parameters, microstructure and resulting magnetic properties, a systematic parameter study has been done in the present work.

DOI:

https://doi.org/10.59499/EP235762561

Authors:

Tomo Takahashi (Pacific Sowa Corporation, Japan), Toshiko Osada (Tokyo Metropolitan University, Japan), Yoshiyuki Kato (Kato Professional Engineer office, Japan), Ken Yokoyama (ExOne KK, Japan)

Abstract:

Gas atomized powders are mainly used in binder jet (BJ) metal 3D printing. The cost of water-atomized powders is lower than that of gas-atomized powders. And surface roughness and mechanical properties of sintered body is improved by using Ultrafine powders obtained through water atomization. However, the flowability of gas atomized powder is lower and the use of them in BJ 3D printing is serious issue. In this study, the flowability of water atomized powders was controlled by addition of nano-silica powder to water atomized powders with different average particle sizes.

DOI:

https://doi.org/10.59499/WP225369747

Authors:

Elodie Cabrol (Centrale Lyon ENISE, France), Hocine Si-Mohand (Centrale Lyon ENISE, France), Agathe Deborde (MetaFensch, France), Jérôme Delfosse (SAFRAN TECH, France), Layla Sasaki (Aubert & Duval, France)

Abstract:

In this work, we have investigated the influence of the presence of satellites on the flowability properties of a TA6V powder. Thermal plasma treatments have been performed to spheroidize the powder at various feed rates (2 to 8 kg|h) under Ar|He atmosphere. The physical and chemical properties of the initial and treated powders have been characterized: morphology, particle size distribution, flow rate, apparent and tap densities, interstitial contents (oxygen, nitrogen and hydrogen). The results have shown that the best powder produced by plasma treatment was spherical, satellites-free and without noticeable effect on the particle size distribution. The Ar|He atmosphere leads to very low interstitial contamination. In addition, an improvement in flow rate of 30% was observed as well as an increase in apparent and tap densities of 20% and 8% respectively.

DOI:

https://doi.org/10.59499/WP225371983

Authors:

Giorgia Lupi (1); João Teixeira Oliveira de Menezes (1); Filippo Belelli (1); Francesco Bruzzo (2); Joerg Volpp (3); Enrique Mariano Castrodeza (1); Riccardo Casati (1)

1- Department of Mechanical Engineering, Politecnico di Milano, Via G. La Masa 34, 20156 Milano (MI), Italy

2- Fraunhofer, Institut für Werkstoff- und Strahltechnik, Winterbergstraße 28, 01277 Dresden, Germany

3- Luleå University of Technology, Department of Engineering Sciences and Mathematics, SE-971 87 Luleå, Sweden

Abstract:

In this work, a mechanical characterization of AlSi10Mg alloy processed by Direct Energy Deposition with Laser Beam of Metals (DED-LB/M) in atmospheric conditions was performed. SE(B) and ESE(T) specimens, for fracture and fatigue tests were printed and machined having the cracks in three different crack plane orientations. Microstructural and fractographic analyses were performed by FE-SEM and LOM, and it was observed that the fracture response is strongly affected by the crack plane orientation and porosity distribution. Moreover, the ESE(T) specimens were analyzed using the EBSD technique and the results shed light on the effect of melt pool boundaries, grain boundaries and crystallographic orientation of grains on the crack path for the different crack plane orientations.

DOI:

https://doi.org/10.59499/EP235765625

Authors:

Markus Schneider (1), Dennis Wawoczny (1), Kevin Haffke (1)

1- GKN Powder Metallurgy Engineering GmbH, Radevormwald, Germany

Abstract:

The critical grain depth of cut hcu, crit. is a grinding metric which controls the transition from a ductile grinding regime to a brittle grinding regime and it can be correlated with several material parameters. A ductile grinding regime is preferred because it does not damage the bulk material. Intermetallic compounds, e.g. sintered Nd2Fe14B hard magnets, are very brittle and therefore prone for chipping defects. The fracture toughness KIc is a relevant factor – with a quadratic effect – in the equation of the critical grain depth of cut hcu, crit. and controls the required grinding process parameters. Anyhow, the conventional plane-strain fracture toughness derivation method with chevron notched 3-point bending specimens is very expensive due to the needed electro discharge machining (EDM) procedure to wire erode the chevron-shaped notch. As an alternative the indentation based Palmqvist toughness method was applied with good results. The derived fracture toughness KIc values are very low but in a reasonable range.

DOI:

https://doi.org/10.59499/EP246319981

Authors:

Núria Cinca (Hyperion Materials and technologies, Spain), Sandra Gordon (Universitat Politècnica de Catalunya, Spain), Mikael Olson (Dalarna University, Sweden)

Abstract:

In many metal forming processes, certain texturization of the tool is necessary to have some friction that can make the operation possible. One example of that is the use of crosshatching methods on cemented carbide punches to manufacture beverage cans. The deep drawing and ironing process of the aluminum foil during can production involves different wear mechanisms being active on the punch surface, i.e. microabrasion and metal transfer. The present work examines the abrasive wear performance and friction characteristics of two cemented carbide grades by means of scratch and linear reciprocating sliding wear testing with Al2O3 counterparts under dry and lubricated conditions, with smooth polished and textured cemented carbide surfaces respectively. Additionally, well-controlled tests in which an aluminum pin is sliding over the cemented carbide surface were performed to evaluate the initial metal transfer. Post-test characterization shows the influence of carbide microstructure on the friction, material transfer and wear

DOI:

https://doi.org/10.59499/WP225368056