World PM2022 Proceedings

Authors:

Jazmina Navarrete Cuadrado (CEIT-BRTA, Spain), Tomas Soria Biurrun (CEIT-BRTA, Spain), Steven Moseley (Hilti Corporation, Liechtenstein), Nerea Gonzalez Polvorosa (Hilti Corporation, Liechtenstein), Jose M. Tarragó (Hilti Corporation, Liechtenstein), Jose M. Sanchez-Moreno (CEIT-BRTA, Spain)

Abstract:

Tungsten borides are potential candidates for the fabrication of tool materials. Among them, tungsten tetraboride is attracting increasing attention due to its very high hardness (» 47 GPa), good electrical conductivity and abrasion and corrosion resistance. Nevertheless, the technologies needed to obtain WB4 based usable tools are still to be developed. In this work, full densification of WB4 based hard materials has been achieved by applying glass encapsulated HIP cycles to powders mixtures with different W|B ratios and Ta additions. Contrary to that reported by other authors, it has been confirmed that Ta addition enhance the transformation of tungsten tetraboride (WB4) into tungsten diboride (WB2). Processing parameters have been tailored for retaining the hard WB4 hexagonal phase after sintering reaching hardness values over 26 GPa (HV5). Interaction between WB4 and different metals has been investigated in order to find suitable binder phases for producing tougher WB4-metal cermets.

DOI:

https://doi.org/10.59499/WP225371740

Authors:

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

Abstract:

Advents in additive technologies have enabled the production of tailormade prostheses for medical applications. This achievement is limited by the yet scarce available commercial materials. This work explores the use of fused filament fabrication for the production of a bone prosthesis of biocompatible CoCrMo alloy. One of the biggest challenges was the design of a highly loaded feedstock capable be turned into a coiling filament adapted to the FFF requirements. A suitable filament was successfully created and printing conditions optimized. A thorough study was carried out to determine debinding and sintering conditions, with particular focus on the dimensional precision, microstructure analysis and hardness test. Finally, the filament was tested for the processing of an acetabular shell for a hip prosthesis with dense|porous zones.

DOI:

https://doi.org/10.59499/WP225372298

Authors:

Karim Asami (Technical University Hamburg, Germany), Dirk Herzog (Technical University Hamburg, Germany), Clarissa Klemp (Technical University Hamburg, Germany), Leon Geyer (Technical University Hamburg, Germany), Claus Emmelmann (Technical University Hamburg, Germany)

Abstract:

Filament-based material extrusion (MEX|M) presents a rapid and inexpensive alternative to e.g. metal injection molding, particularly for prototype production. The filament consists of metal powder in a plastic matrix and is melted and applied layer by layer until a so-called green body is created. These green parts are subsequently debinded and sintered at high temperatures to form a dense metal component. It is crucial to identify the material-specific and process-specific limits in order to be able to manufacture true to size. This paper therefore develops design guidelines for the MEX|M process for green part manufacturing for the widely used austenitic stainless steel AISI 316L (1.4404). Basic geometrical features such as walls, boreholes and overhangs are studied and influencing factors on the dimensional accuracy are assessed. Based on the results, recommendations for part design are presented.

DOI:

https://doi.org/10.59499/WP225371760

Authors:

Flore Villaret (EDF-R&D, France), Yann de Carlan (Université Paris-Saclay, CEA, France), Damien Fabrègue (Université de Lyon, France), Jérôme Garnier (Université Paris-Saclay, CEA, France), Xavier Boulnat (Université de Lyon, France)

Abstract:

The use of different steel powders allows to obtain either multi-material junctions, when they are stacked, or new duplex alloys when they are blended.This study focuses on new materials obtained by Spark Plasma Sintering (SPS) or Hot Isostatic Pressing (HIP) with an austenitic 316L steel and a martensitic Fe-9Cr steel powders. These materials are characterized at different scales: from metallography to electron microscopy with EDX and EBSD, hardness and tensile tests.The mechanical behaviour of materials cannot be described by a simple law of mixtures. To better understand this phenomenon by describing the obtained materials as a composite, Reuss and Voigt models are used and discussed.The microstructural characterizations show that during the consolidation, the diffusion of the chemical species modifies the nature and the amount of phases, which makes it possible to understand why the models do not completely account for the experimental behaviour.

DOI:

https://doi.org/10.59499/WP225371658

Authors:

Alexander Mejía-Reinoso (Universidad Carlos III de Madrid, Spain), Soon-Jik Hong (Kongju National University, Korea, Republic of), JOSE MANUEL TORRALBA (Universidad Carlos III de Madrid, Spain), Monica CAMPOS (Universidad Carlos III de Madrid, Spain)

Abstract:

The microstructure of materials used in high-temperature components such as power generation, aerospace, chemical, and process plant applications must be stable at the service conditions to avoid any losses in the performance. The reduction of density and the increase of the thermal stability range of the microstructure are also two critical improvements to consider in the development of new dual Co-based superalloys. This work explored three viable choices for achieving dual ?|?’ microstructures: the Co-Al-Mo, the Co-Ni-Al-Ta-Ti-V, and the Co-Ti-V. Since the microstructural characteristics of Co-reinforced by ?' superalloys are critical for the envisioned next-generation superalloys, the morphology and coarsening behaviour of the ?' precipitates in each alloy during the sintering process have been investigated. The volume fraction of ?' and whether there is a difference in the coarsening rate of the ?' precipitates are also key factors in the behaviour of these alloys at high temperatures, has been promoted.

DOI:

https://doi.org/10.59499/WP225371699

Authors:

José Luis Aguilar-Garcia (Carlos III University, Spain), Elisa María Ruiz-Navas (Carlos III University, Spain)

Abstract:

This work explores Composite Extrusion Modeling (CEM) with aluminium as an alternative processing route for aluminium alloys. This process allows working with pellets to be deposited directly, layer-by-layer. For this reason, an initial study, necessary for the production of samples, has been carried out. The first challenge was the design of sustainable aluminium-based feedstock, and the production of pellets for additive manufacturing. Thanks to previous studies by the research group, the Powder Injection Moulding (PIM) technique was used as a first approach to produce good quality samples through a combination of water-soluble polymers with low CO2 emissions, PEG and CAB, respectively. For this, a microstructural characterization was carried out and the critical solid loading and rheological properties were studied, as well as the debinding conditions and sintering parameters. In the same way, the printing parameters were optimized for a proper material deposition and to obtain good quality samples.

DOI:

https://doi.org/10.59499/WP225371685

Authors:

Alexey Tatarinov (Riga Technical University, Latvia), Viktors Mironovs (Riga Technical University, Latvia), Viktors Kurtenoks (Riga Technical University, Latvia)

Abstract:

Although the diagnostics of cracks in sintered PM parts can be performed by resonant acoustic inspection, cracks detection in green parts still remains challenging. The problem persists due to the inapplicability of a mechanical impact to brittle green parts and a low mechanical Q-factor resulting in the absence of expressed natural resonances. Cross-correlation analysis applied to vibration spectra in healthy and damaged green PM gears obtained by laser Doppler vibrometry demonstrated minimal discrepancy between healthy parts and strong differences between healthy and cracked parts. To approach a vital industrial implementation, possibilities for an alternative simpler realization were explored. The compared testing modalities included pendulum test with a lightweight platform, contactless excitation by a pulsed electromagnetic action and frequency sweep with an electrodynamic actuator. All testing modalities along with laser vibrometry demonstrated differences in the vibration spectra between healthy and damaged green parts quantitatively assessed by cross-correlation and cross-coherence analysis.

DOI:

https://doi.org/10.59499/WP225367369

Authors:

Gerrit Hellenbrand (Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany), Lukas Klee (Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany), Jens Brimmers (Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany), Christian Brecher (Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany), Thomas Bergs (Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University, Germany)

Abstract:

Due to the remaining porosity of powder metallurgical (PM) gears, the highly stressed surface is post-densified in a cold rolling process to increase the wear resistance. In this report, an approach to determine the maximum possible surface densification of a demonstrator gear is presented. To realise a high degree of deformation and simultaneously avoid spalling damages at the tip area, an adaption of the process kinematic is used. Metallographic microsections are analysed to detect subsurface damages resulting from the cold rolling process. Additionally, the machine traces concerning the upcoming rolling forces over the feed-rate and number of over-rollings are evaluated. Finally, the realised densification profile is evaluated using an image-processing tool, based on the metallographic microsections and a core-density measurement. This profile can serve as an input for an FE-based tooth contact analysis with consideration of the local density profile.

DOI:

https://doi.org/10.59499/WP225372013

Authors:

Berend Denkena (Institute of Production Engineering and Machine Tools, Germany), Benjamin Bergmann (Institute of Production Engineering and Machine Tools, Germany)

Abstract:

The powder mixture properties determine the sintering results of vitrified bonds for grinding tools. In this paper the influence of the mixing process on porosity of the sintered bonds through the bulk density is shown. Therefore, the bulk density of the mixture and the abrasive concentration and sintering temperature and holding time were varied. Porosity, shrinkage and bending fracture stress were determined to evaluate the influence of these parameters on the sintering result. It was shown that there is no significance influence of abrasive concentration, sintering time and temperature on porosity, shrinkage and bending fracture stress. Instead the influence of the abrasive concentration on the porosity of the powder mixture and the influence of the porosity of the powder mixture on the shrinkage was shown. These outcomes are important for designing moulds and optimizing sintering results.

DOI:

https://doi.org/10.59499/WP225370589

Authors:

Nicolas Charpentier (FEMTO-ST, France), Thierry Barrière (FEMTO-ST, France), Nathalie Boudeau (FEMTO-ST, France), Peter Vikner (Aubert & Duval, France)

Abstract:

Bio-based binder alleviate the important carbon footprint that is created during PIM-like process with a carbon cycle for the binder. Moreover, some bio-based polymer are more suited to EAM, like PLA.This work presents the different steps in developing a suitable pellets feedstock for PIM-like EAM and its optimisation to minimize porosity by tomographic observation in the final part. The work is focused in the use of a steel-tool alloy powder but using the same method other materials can broaden the field of application.

DOI:

https://doi.org/10.59499/WP225371909

Authors:

S Venkatesh Kumaran (IMDEA Materials and Universidad Carlos III de Madrid, Spain), José Manuel Torralba (Universidad de Carlos III de Madrid and IMDEA Materials, Spain)

Abstract:

High entropy alloys (HEAs) have garnered significant research attention due to their unconventional alloying approach which results in exceptional properties. Recently, additive manufacturing processes like Selective Laser Melting (SLM) have been used to fabricate HEAs with enhanced mechanical properties. However, SLM processes demand the use of fully pre-alloyed powders since using elemental powders directly might lead to pronounced segregations. However, there are no readymade pre-alloyed HEA powders in the market and pure elemental powders are expensive. So, in this work, commercial commodity powders like Ni 625,CoCrF75, 316L, Invar36, and Fe49Ni which are readily available at competitive prices, were used to make HEAs. The selected powders were mixed in appropriate proportions and printed using SLM. The resultant alloy was a CoCrFeNiMox, with an FCC phase and exhibited promising mechanical properties. This work opens a completely new field of work with multiple possibilities to manufacture HEAs by additive manufacturing at competitive prices.

DOI:

https://doi.org/10.59499/WP225371709

Authors:

Aurelien Etiemble (Université de Lyon, ECAM Lasalle, France), Thierry Commeau (Umicore Specialty Powders France, France), Sandra Simon (Université de Lyon, ECAM Lasalle, France), Claire Rigollet (Université de Lyon, ECAM Lasalle, France)

Abstract:

The applicability and expansion of the promising opportunities offered by extrusion-based technologies for the additive manufacture of metal parts (FFF, FDM or PIM-like) depends on the development of new feedstock for specialty powders. In this context, W-based feedstock was developed and characterized in this study. For these indirect processes, the feedstock is firstly extruded to form a wire and is then deposited to shape the part. Debinding and sintering operations are finally required to obtain the finished metal part. The feedstock formulation was optimized to allow and then to enhance the processability at all these steps. The printability of W-based feedstocks is demonstrated and a critical powder content, required to guarantee the efficient debinding and sintering, is established. Microstructure and mechanical properties (hardness) of sintered parts were characterized and compared to conventionally manufactured parts.

DOI:

https://doi.org/10.59499/WP225371433