World PM2022 Proceedings

Authors:

Yan Liu (Simtec Soft Sweden AB, Sweden), Seyed B. Hosseini (Research Institutes of Sweden AB (RISE AB) | Chalmers University of Technology, Sweden), Mats Persson (Digital Metal, Höganäs AB, Sweden), Zhenghua Yan (Simtec Soft Sweden AB, Sweden)

Abstract:

Binder jetting process is a prominent 3D printing technology due to its cost-effectiveness and capability to scale up the production in terms of batch sizes. However, the green parts need several post-processes including curing, debinding and sintering to improve the parts' density and mechanical strength. These post-processes bring many challenges affecting the final part size and dimensional accuracy. To get the best result and desired material properties, precise temperature and atmosphere control are vital during each individual post-processes. This work shows 3D computational fluid dynamics (CFD) as a powerful tool to obtain such an objective. A full-scale 3D CFD simulation method of a sintering furnace in operation will be presented. This method allows 3D calculation of all the important processes including thermal gradients, gas flowing, thermal radiation, convection and conjugate heat transfer in solids and fluids so that sintering processes of metal binder jetting products can be well simulated.

DOI:

https://doi.org/10.59499/WP225367863

Authors:

Jordan Lacorne (Université de Lyon, INSA Lyon, France), Eric Maire (Université de Lyon, INSA Lyon, France), Xavier Boulnat (Université de Lyon, INSA Lyon, France), Romain Faye (Nanoe SAS, France), Sandra Simon (Université de Lyon, ECAM Lasalle Lyon, France)

Abstract:

Additive Manufacturing is a growing sector in industrial production. Fused Filament Fabrication (FFF) technology is developing by using new materials such as filaments incorporating metal powder (40 to 60%vol) and thermoplastic binders. After 3D printing, FFF needs two more steps: debinding, where the binder is removed, and sintering, where the porous part is densified. The nature of the protective atmosphere is critical because it influences the binder removal and also the sintering|oxidation behavior of the metal powders. This work aims to study the influence of atmosphere (gas type and flow rate) during debinding and sintering on the properties of the final parts in work tool steel (AISI H13). The link between atmosphere and carbon|oxygen uptakes, porosity, microstructure, and mechanical properties will be described.

DOI:

https://doi.org/10.59499/WP225371420

Authors:

Emil Strandh (Swerim AB, Sweden), Cameron Blackwell (MTC, United Kingdom), Martina Meisnar (ESA, United Kingdom), Laurent Pambaguian (ESA, Netherlands), Christian Lockowandt (Swedish Space Corporation, Sweden), Dominique Daab (Swedish Space Corporation, Sweden), Irma Heikkilä (Swerim AB, Sweden)

Abstract:

The effect of variability of metal laser powder bed fusion (L-PBF) processes and raw materials for the shape accuracy of the part is a poorly understood area. A suite of designs covering bulky designs of complex shape and delicate fine features were created and manufactured by different machine hardware, process parameters and four AlSi10Mg powders sourced from different suppliers. The designs were relevant for use in space applications. The aim was to evaluate the relationship between the process and powder characteristics for the shape accuracy using a systematic approach for the investigation. The results showed the shape accuracy was clearly connected to the applied process and indirectly to the powder.

DOI:

https://doi.org/10.59499/WP225370222

Authors:

Theophile Vié (Laboratoire 3SR, France), Barthelemy Harthong (Laboratoire 3SR, France), Philippe François (Rio Tinto Fer et Titane, Canada), Jean Reid (Hl Blachford Ltd, Canada), Jürgen Voglhuber (Miba Sinter Austria GmbH, Austria), Vincent Paris (Rio Tinto Fer et Titane, Canada), Robert Hellein (Miba Sinter Austria GmbH, Austria)

Abstract:

Frictional characteristics of an iron-based mixture were studied using a specifically designed friction test bench allowing (after prior compaction) the measurement of the friction coefficient during the sliding of a compact on a bar simulating the die surface. Temperature and sliding speed were controlled. An experimental campaign was conducted with four high-performance lubricants and a conventional EBS wax, based on a single FL-4400 mix formulation. The experimental parameters included: mix temperatures from 40 to 80°C; density of 7.20g|cc; normal pressure between 150 and 240MPa; sliding distance 80mm; sliding velocity 20mm.s-1. The analyses focused on the evolution of the friction coefficient and the compact’s surface degradation. After multiple repetitions, a steady state was established with a sliding distance beyond which degradation became critical. The degradation depended on the lubricant and experimental conditions. This study aims at better understanding how the friction coefficient evolves during the ejection of a production part.

DOI:

https://doi.org/10.59499/WP225366255

Authors:

Markus Mirz (Institute for Materials Applications in Mechanical Engineering, RWTH Aachen University, Germany), Marie Franke-Jurisch (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Germany), Anke Kaletsch (Institute for Materials Applications in Mechanical Engineering, RWTH Aachen University, Germany), Christoph Broeckmann (Institute for Materials Applications in Mechanical Engineering, RWTH Aachen University, Germany)

Abstract:

The main purpose of evacuation tubes in powder metallurgically-based (PM) Hot Isostatic Pressing (HIP) lies in the evacuation and outgassing of the capsule. Conventional HIP capsules are made of sheet-metal which exhibits good weldability and therefore, it is easy to join the evacuation tube. With the emerging technologies of Additive Manufacturing (AM) it is now possible to design more complex capsules for HIP. Additionally, wear-resistant materials can be utilized. Yet, these materials are known to be difficult to weld. This study compares three different approaches to bond an AISI 304 evacuation tube to a HIP capsule made by Electron Beam Melting (EBM) from high carbon tool steel AISI A11. Capsules were bonded by TIG welding as well as brazing with conventional and a customized filler material based on thermodynamic calculations. Subsequent consolidation by HIP, microstructural analysis and argon-measurements revealed the feasibility and limits of all three approaches for gas-tight bonds.

DOI:

https://doi.org/10.59499/WP225370176

Authors:

Oliver Schenk (RWTH Aachen University, Germany), Yuanbin Deng (RWTH Aachen University, Germany), Christoph Broeckmann (RWTH Aachen University, Germany)

Abstract:

A digital twin offers the potential of understanding and improving production processes by using numerical models. Although multiple approaches of digital twins were reported, most of them only focus on the macroscale. However, the microstructural evolution is often crucial for the application of products. For instance, the pore morphology which determines the final mechanical properties is highly affected by the compaction and sintering steps in the PM process chain. In this work, a digital twin was developed to model the compaction and sintering of water-atomized Astaloy 85Mo on a mesoscale. Scanning electron microscopy images of green body microstructures were used to train a generative adversarial network to predict the microstructure dependent on the powder particle size. The evolution of these artificial microstructures during sintering due to surface diffusion was subsequently simulated with the level-set-method. The obtained sintering kinetic agrees well with that calculated by analytical equations of sinter neck growth.

DOI:

https://doi.org/10.59499/WP225371655

Authors:

Lucia De Bortoli (University of Trento, Italy), Sasan Amirabdollahian (University of Trento, Italy), Stefano Rappo (Lincotek Medical, Italy), Matteo Perini (ProM facility, Trentino Sviluppo, Italy), Alberto Fabrizi (University of Padova, Italy), Alberto Molinari (University of Trento, Italy)

Abstract:

In the production of Co alloy | Ti alloy bimetallic components by Laser Directed Energy Deposition (L-DED), one critical issue is the microstructure of the metallurgical bonding layer produced by the melting of the substrate. This layer has a complex microstructure resulting from the mixing of the two alloys in liquid state and solidification. To investigate such a microstructure, specimens with a different content of the two alloys were produced by SPS and melted by laser, with the working parameters typical of the L-DED process. The solidified microstructure is quite complex. The SEM-EDXS and EBDS analyses show the partitioning of Ti, Co and the alloying elements in different compounds and phases depending on the relative amount of the two alloys. The tendency to cracking shows a dependence on the microstructure.

DOI:

https://doi.org/10.59499/WP225371926

Authors:

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

Abstract:

A multiscale study of boron, carbon behavior and the microstructure of PM HIP compact from high temperature Ni-based superalloy produced using PREP-powder under tensile testing at high temperature was performed. This study of boron and carbon behavior related to the microstructure of the necking and fracture zones, was carried out by direct methods track autoradiography on boron using the nuclear reaction 10B(n, a)7Li and activation autoradiography on carbon using the nuclear reaction 12C(d, n)13N, metallography, SEM, EDX, OIM methods. The formation of a mesocrack was revealed as the localization of plastic deformation before fracture, followed by a significant migration of boron and, to a lesser extent, carbon, precipitation of boride and carbide phases in the loop of maximum shear stresses for the mesocrack and in shear bands. It is important, that Intensive boron migration begins in the diffuse neck. The results revealed are explained by dynamic strain aging

DOI:

https://doi.org/10.59499/WP225367097

Authors:

Emir Poskovic (Politecnico di Torino, Italy), Marta Ceroni (Politecnico di Torino, Italy), Fausto Franchini (Politecnico di Torino, Italy), Luca Ferraris (Politecnico di Torino, Italy), Marco Actis Grande (Politecnico di Torino, Italy)

Abstract:

Soft Magnetic Composites (SMC) comprise magnetic grains held together by an insulating layer. The widespread diffusion in the market for such materials, conventionally employed in electrical machines, is currently held back by limitations associated with material properties and processing constraints. These drawbacks are mostly related to the insulating layer employed. This contribution aims at overcoming such limitations by means of a novel surface approach. The proposed surface modification allows to coat of each particle with a nanostructured layer providing electrical insulation while also conferring additional features such as improved mechanical properties and withstanding higher treatment temperatures. In addition, the use of the proposed technology makes the layer feasible with a wide range of materials. The layer materials can be organic, inorganic or a combination of both. SMCs encompassing the developed innovative multi-functional layers have been prepared and characterized by means of surface morphology, magnetic and mechanical properties.

DOI:

https://doi.org/10.59499/WP225371894

Authors:

Markus Schneider (GKN Sinter Metals Engineering GmbH, Germany), Tina Schlingmann (EOS GmbH, Germany), Dirk Bettge (Bundesanstalt für Materialforschung und -prüfung, Germany), Kai Hilgenberg (Bundesanstalt für Materialforschung und -prüfung, Germany), Maximilian Binder (Fraunhofer-Institut für Gießerei-, Composite- und Verarbeitungstechnik, Germany), Burghardt Klöden (Fraunhofer-Institut für Fertigungstechnik und Angewandte Materialforschung, Germany)

Abstract:

When it comes to higher accuracies, new technologies and real applications in additive manufacturing, there is one topic which cannot be avoided: The material response on the chosen processing parameters and its agreement and correspondence with literature data of the wrought material grade counterpart. In industrial additive manufacturing standards in terms of printing parameters, protection gas atmospheres or powder handling instructions are not obligatory. Therefore, the question must be answered whether the additive manufacturing process is reproducible and reliable over different printing companies. This was the motivation to realize a round robin test between 8 European printing companies and academic partners. The consortium had printed and tested fatigue and tensile testing bars under plant-specific conditions. A commonly used cast aluminum alloy, AlSi10Mg, was chosen as test material for the PBF-LB|M process. Differences of the results between the partners and the scatter itself were discussed in detail.

DOI:

https://doi.org/10.59499/WP225377471

Authors:

Shandra Sainz (CEIT, Spain), Odei Ruiz (CEIT, Spain), Iñigo Iturriza (CEIT, Spain), Brian Kernan (Desktop Metal, USA), Ashley Morishige (Desktop Metal, USA), Steve Hudelson (Desktop Metal, USA), Francois Dary (Desktop Metal, USA)

Abstract:

Single Pass JettingTM technology was explored using the Desktop Metal’s Production SystemTM P-1 to develop a 440C stainless steel with Nb addition. A MIM powder grade was used as the raw material and the complete process towards its densification has been defined, from the selection of the appropriate powder conditioning and printing parameters to the identification of the sintering and heat-treating cycles considering metallurgical criteria. On those grounds, C and Nb content as well as the sintering atmosphere play a critical role. Chemical analysis and metallographic characterization were performed to analyse the evolution of the porosity and the microstructure. The steps of the heat treatment were selected based on retained austenite monitoring and a target hardness of 58±1 HRC. Testing samples were printed to evaluate the tensile and impact properties of the alloy against Standard MPIF35 .

DOI:

https://doi.org/10.59499/WP225372017

Authors:

Tobias Deckers (Linde GmbH, Germany), Thomas Ammann (Linde GmbH, Germany), Kai Zissel (Linde GmbH, Germany), Franz Wolf (Linde GmbH, Germany), Gerd Witt (University Duisburg-Essen, Germany)

Abstract:

This paper aims to investigate the influence of the process gas atmosphere during the Powder Bed Fusion of Metals using a Laser Beam (PBF-LB|M) of a Nickel-Chromium alloy on the melt pool geometries of single laser tracks and on the discoloration of process by-products. The trials were performed on an EOS M290, which was equipped with a photodiode-based melt pool monitoring system (MPM). First results indicated differences in the intensity levels of the MPM signal and in the penetration depths. Furthermore, a correlation between the discoloration of the sampled powder material and the intensity level of the MPM signal was detected.

DOI:

https://doi.org/10.59499/WP225372132