Individual Papers

Authors:

T. Mossop (1), DJ Browne (1), M. Celikin (1)

1- School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland

Abstract:

Processing β-titanium (Ti) alloys via metal additive manufacturing (AM) has high potential to be used for biomedical applications, hence understanding their solidification behaviour under rapid cooling is critical. The solidification structures of Ti-niobium-tantalum (Ti-Nb-Ta) based alloys were investigated under various cooling rates (c. 2,000-20,000 K/s) using rapid solidification suction casting. An anti-solute trapping effect was determined for a ternary Ti-Nb-Ta alloy. In relatively slower-cooled samples, the microsegregation was in line with Scheil-Gulliver theory, however under more rapid cooling, the microsegregation increased significantly. This anomalous microsegregation had the effect of stabilizing additional α/α’- and β-phase content of the as-solidified ternary alloy – reducing the otherwise favoured martensitic α’’ content and resulting in a dual-phase structure where the dendrites are primarily β-phase and the interdendritic regions are α’’ martensite.

DOI:

https://doi.org/10.59499/EP246281565

Authors:

Martin Bram (1), Monica Keszler (1), Felix Großwendt (2), Sebastian Weber (2)

1- Forschungszentrum Jülich GmbH, Germany

2- Ruhr-Universität Bochum, Germany

Abstract:

The grinding of steel tools to the final shape generates sludge containing metallic swarf considered undesirable for direct recycling. After cleaning and separation of this steel swarf, its morphology often leaves it inappropriate for standard powder metallurgical uses. However, the possibility exists of utilizing field assisted sintering techniques to densify this swarf directly into new parts, thereby avoiding the need for remelting. This technique also allows for the generation of new metal matrix composites through its quick sintering time. The application of field assisted sintering as a recycling tool is realized through the densification of two different steels, PM T15 and D2, exploring the influence of varied parameter sets and tool setups on their sintering. For proof of concept, a cutting disc made of D2 swarf has been produced, which will be tested in the near future.

DOI:

https://doi.org/10.59499/EP246280685

Authors:

Paria Karimi (1), Esmaeil Sadeghi (1)

1- OptiFab Technologies, Ontario, Canada

Abstract:

This study investigates the influence of novel scan patterns on the microstructure and hardness of γ-TiAl base alloy manufactured using the electron beam-powder bed fusion process. Different scan patterns were explored for their effects on thermal history and heat transfer, resulting in diverse microstructures from fully lamellar to duplex structures. As-built samples with varied scan patterns underwent hardness testing, elucidating differences in hardness qualities. The formation mechanisms of desired microstructures for each scan pattern were extensively examined. The findings provide a valuable framework for tailoring materials with specific microstructures and performance attributes by adjusting scan patterns during electron beam-powder bed fusion, with significant implications for future applications.

DOI:

https://doi.org/10.59499/EP246282019

Authors:

Gunnar Walther (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), Tilo Büttner (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), Christian Imanuel Bernäcker (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), Lars Röntzsch (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), Thomas Weißgärber (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), JungSuk Bae (Alantum Corporation, Korea, Republic of), Lars Torkuhl (Alantum Europe GmbH, Germany), Andreas Tillmann (Alantum Europe GmbH, Germany)

Abstract:

Open cell metallic foams are suitable for a wide range of applications as materials for filters, catalyst supports for heterogeneous catalysis and electrodes in batteries, fuel cells and electrolyzers due to their excellent heat and mass transfer, low pressure drop, good electrical conductivity and high chemical resistance. The foam can be produced in a wide range of pure metals like nickel, iron, silver and copper. Depending on the application, high high-temperature, oxidation and corrosion resistance can be achieved by a patented powder metallurgical alloying process in industrial scale.In the current paper, results for applications of NiFeCrAl foam as catalyst for Steam Methane Reforming and silver foam for the formaldehyde synthesis are discussed. Another focus is on the application as electrode material in electrolysis. Electrochemical investigations show that modified nickel foam exhibit a much lower overvoltage than nickel sheets and thus the operating costs of electrolyzers can be significantly reduced.

DOI:

https://doi.org/10.59499/WP225371743

Authors:

Pelle Mellin (1), Johannes Gårdstam (2), Stefan Heino (1), James Shipley (2), Anders Magnusson (2), Fredrik Forsberg (3), Björn Forsgren (4), Per Waernqvist (4)

1- Swerim AB, Kista, Sweden

2- Quintus Technologies AB, Västerås, Sweden

3- Luleå University of Technology, Luleå, Sweden

4- Ringhals AB, Väröbacka, Sweden

Abstract:

Pores in cast, compacted or AM built material that shrink during HIP, can regrow if they are filled with argon and are subjected to high temperature. To better understand this, we present a study on a set of capsules that contain a huge 2 cm3 cavity. These cavities were filled with argon by sealing them under 1 atm of 100% argon. Using HIP (equipped with URQ) these cavities shrink to an approximate size of 0.006 cm3 resulting in a room temperature pressure of ~340 bars. Upon stepwise reheating the pressure increases, and for IN718 the cavity expands above 900 °C (pressure is here ~1400 bar), while for 316L the cavity expands above 1000 °C (pressure is here ~1450 bar). The temperature at which expansion occurs are not far from typical HIP conditions, which makes sense. The pressure inside a pore appears to be a good indicator for if expansion will occur.

DOI:

https://doi.org/10.59499/EP246280783

Authors:

M. Bemani (1,2,4), W. Sjöström (5), Roos. S (5), Parareda (1), M. Mares (1), A. Mateo (2), R. Das (4),A. Molotnikov (4), C. Botero (5), D. Casellas (1,3)

1-Eurecat, Centre Tecnològic de Catalunya, Metal Digital Manufacturing JRU, Spain

2-CIEFMA – Department of Materials Science and Engineering, EEBE, Universitat Politècnica de Catalunya, Spain

3-Luleå University of Technology, Division of Mechanics of Solid Materials, Sweden

4-Centre for Additive Manufacturing, School of Engineering, RMIT University, Australia

5-Department of Quality Technology and Mechanical Engineering, Sports Tech Research Centre, Mid Sweden University, Sweden

Abstract:

Surface roughness of the additively manufactured (AM) parts can reduce the service life, especially under dynamic loadings, due to promoting fatigue by providing initiation sites for fatigue cracks. Therefore, improving the surface condition of AM specimens can be a solution to increase the fatigue strength. The stiffness method is a rapid fatigue test method that allows to obtain reliable fatigue limit values in a cheaper and easier way than traditional methods. Consequently, this work aims to investigate the effect of surface roughness on the fatigue behavior of stainless steel AISI 316L specimens using the stiffness method. These specimens were printed with laser and electron beam powder bed fusion techniques. Different contour parameters were utilized to obtain different surface roughness values. The competitional effect of the internal defects, which become surface defects after machining, and the surface roughness of the as-built specimens, is also addressed by the stiffness method results.

DOI:

https://doi.org/10.59499/EP246276182

Authors:

J. Horky (1), E. Ariza-Galván (1), A. Zunghammer (2), N. Moser (2), C. Edtmaier (2), T. Klein (3), M. Schmitz-Niederau (4), E. Neubauer (1)

1- RHP-Technology GmbH, Seibersdorf, Austria

2- Institute of Chemical Technologies and Analytics, TU Wien, 1060 Vienna, Austria

3- LKR Light Metals Technologies Ranshofen, Austrian Institute of Technology, 5282 Ranshofen, Austria

4- Voestalpine Böhler Welding Germany GmbH, 59067 Hamm, Germany

Abstract:

Plasma Metal Deposition is a manufacturing technology which allows the fabrication of large structures. Especially for space relevant components with sizes larger than 0.5 meter, it offers a potential to fabricate parts made from light-weight metals with enhanced stiffness. The PMD process uses a plasma welding torch where powder or wire is used as a feedstock. The layer-by-layer processing allows to realize near-net-shape structures. Especially by using powder as a feedstock, there is a large flexibility in creating various alloys as well as metal matrix composites with modified properties. The aim of this study was to improve the specific modulus (ratio of Young´s modulus/density) by introducing ceramic particles into a titanium matrix. Besides addressing the main challenges in the manufacturing of composites by blown powder methods, an overview on various particles is provided. Based on microstructural analysis and mechanical testing, the influence of the different ceramic fillers is discussed.

DOI:

https://doi.org/10.59499/EP235765700

Authors:

Henrik Karlsson (1), Rasha Alkiasee (1), Rasmus Kristensen (1), Peter Harlin (2), William Hearn (3), Eduard Hryha (3)

1- Volvo AB, Sweden

2- Sandvik AB, Sweden

3- Chalmers University of Technology, Sweden

Abstract:

Additive manufacturing (AM) has developed and expanded into new segments the recent years. Nonetheless, the automotive industry has so far not implemented AM to any larger extent, one reason being that the availability of materials for AM has been limited. However, recently several low-alloyed carbon-containing steels suited for the automotive segments have been developed for AM. This paper addressed the heat treatment of AISI 4140 (42CrMo4) and its effect on microstructure and residual stresses. Tests have been carried out on an engine component manufactured by Powder Bed Fusion-Laser Beam process (PBF-LB) and varying subsequent heat treatments. It was found that in a regular quench and temper cycle the parts achieved a similar residual stress state as conventionally manufactured AISI 4140. Samples exposed to a direct temper cycle (tempering only after PBF-LB), showed promising results in terms of residual stresses and metallographic aspects. From the results it is concluded that the current investigation can serve as a basis to further optimization of heat treatment cycles to better utilize PBF-LB/AISI 4140 steels in the automotive sector.

DOI:

https://doi.org/10.59499/EP246278564

Authors:

Erika Tuneskog (1), Lars Nyborg (1), Karl-Johan Nogenmyr (2)

1- Chalmers University of Technology, Sweden

2- CSiemens Energy AB, Sweden

Abstract:

Metal additive manufacturing (AM) enables intricate designs, particularly beneficial for complex fluid applications in gas turbines. Despite its advantages, AM introduces higher surface roughness compared to conventional technologies. In the powder bed fusion–laser beam (PBF-LB) process, surface roughness elements can create blockages in small channels, leading to increased friction. Understanding how features like adhering powder particles, spatter, and melt tracks interact with fluid flow is essential for modeling friction in channel flows. This study statistically characterizes surface roughness variation, considering printing parameters and orientation, utilizing optical profilometers and microscopy. Test samples in stainless steel 316L include flat surfaces and channels oriented from 0° to 90° with 20° intervals. Adhering powder particles are primary inducers of channel roughness, exhibiting positive skewness and high slopes. The density of powder particles on flat surfaces is significantly lower. Therefore, other variables including melt tracks, printing direction, and power input, influence surface characteristics more.

DOI:

https://doi.org/10.59499/EP246281948

Authors:

Kai Zissel (Linde GmbH, Germany), Elena Bernardo Quejido (Linde GmbH, Germany), Pierre Forêt (Linde GmbH, Germany), Eduard Hryha (Chalmers University of Technology, Sweden)

Abstract:

Binder Jetting (BJT) is a binder-based Additive Manufacturing technology, where only a small fraction of the processed powder is bonded inside the green parts after printing. Unbound powder, which is recovered during the BJT process, is reused for printing. For powder reuse, the resulting changes in the physical and chemical powder properties along with the powder surface conditions strongly affect the reproducibility of the BJT process and its final part properties. In this study, the powder degradation and its impact on the reusability of 17-4 PH stainless steel powder are evaluated for the BJT process. Powder characteristics are analyzed after multiple reuse cycles after different process steps, namely drying, sieving, printing and curing. The influence of reused powder on print quality and green densities is investigated and compared to virgin powder. Furthermore, the effect of inert and reducing atmospheres on the powder reusability during curing is examined.

DOI:

https://doi.org/10.59499/WP225371888

Authors:

Abdolreza Simchi (Sharif University of Technology, Iran), Frank Petzolfdt (Fraunhofer Institute IFAM, Germany), Sebastian Boris Hein (Fraunhofer Institute IFAM, Germany), Lea Reineke (Fraunhofer Institute IFAM, Germany), Bastian Barthel (Fraunhofer Institute IFAM, Germany), Daniel Hosseini (Sharif University of Technology, Iran)

Abstract:

Sintering anisotropy is the major challenge limiting the fabrication of large and complex-shaped parts by binder jet additive manufacturing. We employed 3D shell binder jetting to fabricate green parts with a minimum heterogeneity in the pore structure. The advantages of the process include fast printing speed, minimum consumption of the binder, easier de-powdering|de-binding processes, and homogeneous sintering shrinkage. The applicability of the shell printing process for the fabrication of 316L and Ti-6Al-4V parts is demonstrated. Using dilatometric analysis, we show that the sintering shrinkage in different directions only varies by about 1%; hence, deflection during high-temperature sintering is prohibited. The fine and uniform pore structure also renders reduced sintering temperature and time, yielding finer microstructural features and superior mechanical properties. The 3D shell printing could overcome the main limitations of the 3D binder jetting process; hence, it has a great potential to be employed for versatile materials systems.

DOI:

https://doi.org/10.59499/WP225371865

Authors:

Naiara Azurmendi (Tecnalia, Spain), Asier Lores (Tecnalia, Spain), Andoni Laskurain (NUEVA HERRAMIENTA DE CORTE (TIVOLY), Spain)

Abstract:

Binder Jetting Additive Manufacturing technology permits the processing of a wide range of different metallic alloys which cannot be easily manufactured by other AM means, as they may present undesired microstructures or anisotropic functional properties. For this reason, it has been found that BJ can be a suitable AM technology for processing tool steels and obtaining high quality parts with isotropic properties. In the present work, commercial M2 tool steel powder was studied and processed by Binder Jetting under different processing conditions. After some optimization work, near full density was achieved (>99%), together with MIM-like microstructure and hardness (51 HRC). Therefore, this study demonstrates that good quality M2 parts can be obtained by means of BJ, opening new design and manufacturing possibilities for more complex and advanced tooling applications.

DOI:

https://doi.org/10.59499/WP225371923