Individual Papers

Authors:

Federico Simone Gobber (1), Antonio Pennacchio (1), Marco Actis Grande (1), Paolo Priarone (2)

1- Department of Applied Science and Technology, Politecnico di Torino, Alessandria, Italy

2- Department of Management and Production Engineering, Politecnico di Torino, Torino, Italy

Abstract:

Sustainability in production processes is a crucial topic that ensures the responsible use of resources, minimizes environmental impact, fosters long-term viability, and aligns economic success with ecological and social well-being. Regarding powder production via gas-atomization, powder quality and powder yield represent the main aspects to be maximized in order to achieve a robust process. However, gas-atomization energy consumption varies depending on gas-atomization pressure, heating time, power, and consumable reuse. This study proposes a methodology to optimize gas-atomized powder production by reducing the equivalent carbon generated per kilogram of powder. The methodology incorporates particle size distribution, morphology, and environmental impact considerations. The article reports a comprehensive case study for super-duplex steel powders produced by a lab-scale inert gas atomizer. The purpose of the study is to present a general methodology to evaluate the sustainability of gas – atomized powder.

DOI:

https://doi.org/10.59499/EP246282648

Authors:

Moritz Greifzu (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Fabian Peter (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Tarang Dineshchandra Mehta (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Joanna Eckardt (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Sohan Acharya (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Axel Marquardt (Technische Universität Dresden, Germany), Lukas Stepien (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Elena Lopez (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Frank Brückner (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Christoph Leyens (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany)

Abstract:

Binder jetting (BJ) is a sinter-based additive manufacturing technology with several advantages over laser or electron beam-based powder bed processes. This includes faster build rates, non-necessity of support structures and no introduction of thermal stress into the part during the build. On the other hand, BJ parts shrink considerably during sintering making it more challenging to produce parts within tolerances. Recently, software to simulate and compensate this distortion has been commercialized. Since the algorithm is based on a phenomenological model, experiments have to be conducted to feed material parameters into this model for correct simulation of a specific alloy. Here, an experimental approach is presented using dilatometry and in-situ gravitational beam bending to perform a full characterization of stainless steel powder 316L , and the extraction of the relevant data for the simulation.

DOI:

https://doi.org/10.59499/WP225371941

Authors:

Louis Becker (1), Felix Radtke (2), Jonathan Lentz (1), Simone Herzog (2), Christoph Broeckmann (2), Sebastian Weber (1)

1- Chair of Materials Technology (LWT), Bochum, Germany

2- Institute of Applied Powder Metallurgy and Ceramics (IAPK), Aachen, Germany

Abstract:

Laser Powder Bed Fusion/Metal (PBF-LB/M) shows great promise for industrial applications, but its extended production time remains a challenge. To address this, innovative methods such as the shell-core approach have been developed. In this procedure, a component is created with a dense outer shell surrounding a core of either unexposed or minimally exposed powder, drastically reducing processing time. Full densification and specific property adjustment are achieved by subsequent hot isostatic pressing (HIP). This study demonstrates the use of shell-core specimens made from a powder blend of austenitic stainless steel and Si3N4 to produce high-nitrogen steel components that are otherwise difficult to produce due to limited nitrogen solubility in the steel melt. During HIP, Si3N4 dissolves into the austenitic matrix, enriching it with nitrogen and circumventing solubility issues. This results in a material with increased strength and potentially improved corrosion resistance due to the beneficial impact of nitrogen on steel properties.

DOI:

https://doi.org/10.59499/EP246252913

Authors:

Merlin Thamm (1), Inge Lindemann-Geipel (1), Christoph Höhnel (1,2), Thomas Hutsch (1), Shufan Wang (3), Yuanbin Deng (3,4), Christoph Broeckmann (3,4), Thomas Wentzlik (5), Tobias Trupp (5), Thomas Weißgärber (1,2)

1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany

2- TUD Dresden University of Technology, Faculty Mechanical Engineering, Institute of Materials Science, Chair Powder Metallurgy, Germany

3- Institute of Applied Powder Metallurgy and Ceramics at RWTH Aachen e.V. (IAPK), Germany

4- Institute for Materials Applications in Mechanical Engineering (IWM), RWTH Aachen University, Germany

5- Magnetec GmbH, Germany

Abstract:

Within the public founded project “NanoKompakt”, the powder of initial amorphous soft magnetic alloy Vitroperm (Fe73.6Si15.5B6.9Cu1.0Nb3.0) is compacted to nanocrystalline components by FAST/SPS. The aim is to manufacture industrially relevant components such as E-cores that cannot be produced from wounded ribbon. The increased mechanical stability allows for omitting a polymer case, which increases the possible application temperature. Firstly, small toroidal cores were compacted. A high permeability of 20 000 and a low coercivity of 3 A/m are achieved. Based on the thermal and electrical properties of the compacted toroidal cores, a larger pressing tool is also designed and optimized by simulation. The simulation is necessary because the temperature range for compaction is only a few Kelvin wide and the precipitation of hard magnetic phases must be prevented. In the second step, E-cores are cut from compacted slices and analyzed.

DOI:

https://doi.org/10.59499/EP246279398

Authors:

A.V. Shulga

National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 31 Kashirskoe Sh., Moscow 115409, Russian Federation

Abstract:

Based on the results of a multiscale experimental study of the behavior of boron, carbon, and micro-structure of HIP PM compacts of the high temperature Ni-based superalloys, during various heat treatments, as well as compression and tensile tests, performed in particular by the method autora-diography, was constructed the firstly proposed TTT diagram. Study of boron and carbon behavior in relation to microstructure was carried out by direct methods track autoradiography on boron and activation autoradiography on carbon, metallography, SEM, EDX, OIM methods. Formation of solid solution of boron, segregation of boron, and precipitation of borides, in particular, along grain bound-aries as a result of heat treatment of compacts, have been revealed and analyzed. Therefore, the time -temperature conditions for the precipitation of the boride phase were determined as the main parameters of the proposed TTT-diagram of the boride phase in comparison with the TTT-diagrams of the carbide and gamma-prime phases.

DOI:

https://doi.org/10.59499/EP235753737

Authors:

Sibel Yöyler (1), Andrei Surzhenkov (1), Maksim Antonov (1), Mart Viljus (1), Rainer Traksmaa (1), Kristjan Juhani (1)

1- Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Tallinn

Abstract:

Fe-based hardfacing with TiC reinforcement receives considerable attention due to the optimal quality-price ratio. The present research focuses on the investigation of microstructure and abrasive wear behavior of Fe-based hardfacing with TiC, in-situ synthesized from TiO2. The plasma transferred arc (PTA) cladding method was used for in-situ synthesis of TiC on the S235 steel substrate using 72 hours ball-milled AISI 316L stainless steel (ss), TiO2, and graphite powders. Scanning electron microscopy (SEM) was used to analyze the microstructure, and energy dispersive spectroscopy (EDS) analysis was used to determine the distribution of TiC. XRD analysis was used to define the phase composition. Vickers hardness was measured, and ASTM G65 abrasion test was applied to evaluate the wear resistance of the hardfacings. Wear mechanisms were studied under SEM.

DOI:

https://doi.org/10.59499/EP235762969

Authors:

Lea Reineke (Fraunhofer IFAM, Germany), Bastian Barthel (Fraunhofer IFAM, Germany)

Abstract:

Metal Binder Jetting (MBJ) has an increasing attention in additive manufacturing because of its serial production potential. The aim of this work is to achieve the most suitable parameterization of the MBJ printing processes for specific powder-binder combinations, based on the powder characteristics and the powder-binder interaction. Depending on wetting properties and acting capillary forces, some MBJ powders need more or less binder to generate parts with optimal properties. The use of too high binder saturations generally leads to density loss due to binder application, as well as increased carbon content of the final sintered part or even loss of geometrical features. Too low saturations result in low green strength as well as low part accuracy. The economic background of the development of pre-printing tests is a reduction in the number of iteration stages in material-specific process development, which saves costs, effort as well as material resources and printing capacity.

DOI:

https://doi.org/10.59499/WP225367722

Authors:

Laura Cordova (1), Fouzi Bahbou (2), Eduard Hryha (1)

1- Chalmers University of Technology, Chalmersplatsen 4, 412 96 Göteborg, Sweden.

2- Arcam AB/GE Additive, 435 33 Mölnlycke, Sweden

Abstract:

Processability in Powder Bed Fusion - Electron Beam (PBF-EB) depends on the number of factors, covering homogeneous powder bed, powder chemistry and interaction of the electron beam with the metal powder. For a good, consolidated part to be processed, the powder must be smoothly applied on the powder bed and the beam transmits the electrons throughout the powder layers. Only with powder of specific characteristics, e.g. narrow PSD, smooth and spherical morphology, high chemical purity this is possible. In this study two different TI6Al4V powder batches are analyzed, where one batch presented challenges with processability even in virgin state. For both powders, an assessment of the morphology, particle size, rheology, and chemistry will determine the feasibility to achieve optimal processability and the possibility to reuse in consecutive cycles.

DOI:

https://doi.org/10.59499/EP235765563

Authors:

Stefan Marschnigg (1), Christopher Herzig (1), Andreas Limbeck (1), Herbert Danninger (1), Christian Gierl-Mayer (1); Thomas Weirather (2,3), Thomas Granzer (2)

1- Technische Universität Wien, Institut für Chemische Technologien und Analytik, Getreidemarkt 9/164, A-1060 Wien, Austria

2- Plansee Composite Materials GmbH, Siebenbürgerstrasse 23, D-86983 Lechbruck, Germany

3- CERATIZIT Austria GmbH, Metallwerk-Plansee-Straße 71, A-6600 Reutte, Austria

Abstract:

Tungsten heavy alloys are liquid phase sintered two-phase materials in which tungsten grains are embedded in an austenitic base matrix. While the solubility of W in the binder phase is high both at sintering temperature, when the binder phase is liquid, and also after cooling, the solubility of the binder elements in the W phase is very low, but the exact content has been a matter of discussion for a long time. In the present study, laser ablation induction coupled plasma mass spectrometry (LA-ICP-MS) has been employed for analyzing the Ni and Fe content in the W phase of W-Ni-Fe heavy alloys, using specifically prepared low-binder specimens for calibration. It showed that the binder element content is in fact significantly lower than presented in the literature, LA-ICP-MS yield-ing contents of approx. 340 µg/g for Fe and 60 µg/g for Ni.

DOI:

https://doi.org/10.59499/EP235755779

Authors:

Koji Nakamura (Kyushu University, Japan), Isshin Ando (Kyushu University, Japan), Masatoshi Aramaki (Kyushu University, Japan), Fei Jiang (Yamaguchi University, Japan), Takeshi Tsuji (the University of Tokyo, Japan), Kosuke Ashizuka (JFE Steel Co., Japan), Masayuki Uesugi (Japan Synchrotron Radiation Research Institute (JASRI), Japan), Akihisa Takeuchi (Japan Synchrotron Radiation Research Institute (JASRI), Japan), Yukiko Ozaki (Kyushu University, Japan)

Abstract:

For a high-density pure iron sintered compact without open pores, the 3D pore configurations at different strain levels during ductility tests were visualized by X-ray computed tomography (CT). In addition, each three-dimensional structure was quantified as a two-dimensional scatter plot, persistent diagram, by 1st persistent homology (PH) analysis. By comparing the scatter plots, specific local pore configurations sensitive to changes in strain were extracted. The results showed that, just prior to fracture, adjacent closed pores formed pore-clusters and coalesce to each other into larger pores. This process is consistent with the theory of ductile fracture of the void model proposed for wrought metals.

DOI:

https://doi.org/10.59499/WP225372227

Authors:

Marco Zago (University of Trento, Italy) Giacomo Segata (University of Trento, Italy) Sabrina Veronesi (University of Trento, Italy) Matteo Perina (Mimest, Italy) Ilaria Cristofolini (University of Trento, Italy)

Abstract:

Metal Binder Jetting (MBJ) is an additive manufacturing (AM) technology increasingly gaining interest due to its capability of producing complex products in medium-large batches, cost-effectively compared to other AM technologies. Nevertheless, dimensional accuracy is still challenging, considering the significantly anisotropic shrinkage on sintering. The influence of printing parameters on the anisotropic shrinkage of two different geometries is studied in this work. Using fractional factorial Design of Experiments (DOE), four factors at three levels were considered (printhead speed, binder saturation, rake speed, and shell thickness). 30 cubes with squared through-hole, and 30 cylinders with circular through-hole were produced for each experiment using 316L; the shrinkage along different printing directions was derived from the dimensions measured at green and sintered state by Coordinate Measuring Machine. The optimal combination of printing parameters for the different geometries was identified using ANOVA. The effect of printing parameters on the two geometries was highlighted and discussed.

DOI:

https://doi.org/10.59499/EP256767057

Authors:

Andrey Shulga (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Russia)

Abstract:

The occurence of anomalous particles (granules) with significantly different content of interstitial microalloying elements carbon and boron is an important features of the homogeneity of the composition of rapidly quenched powders of stainless steels and Ni-based superalloys produced by the PREP method. A multi-scale experimental investigation of the evolution of the structure of the PM HIP stainless steels under hot deformation and heat treatment was performed. Direct nuclear methods of activation autoradiography on carbon, track autoradiography on boron, metallography, SEM, EDX, and OIM were used to reveal the evolution of the microstructure of the PM HIP stainless steels. A significant effect of hot deformation and heat treatment on the behavior of carbon and boron in PM HIP stainless steels has been revealed in comparison with their traditional counterparts. Essential lnfluence of the evolution of carbon and boron on the mechanical properties of PM HIP stainless steels was found

DOI:

https://doi.org/10.59499/WP225369660