• Authors:

    Ali Rajaei (1), Valérian Iss (1), Christoph Broeckmann (1)

    1- Institute for materials applications in mechanical engineering (IWM) of the RWTH Aachen University

    Abstract:

    The performance of Powder metallurgical (PM) gears must be increased towards the level of the conventional high strength gears for a reliable application in automotive transmission. To this end, the potentials of the PM production of gears must be fully utilized. Surface densification and hardening of sintered gears are examples of economically plausible measures to increase the strength of these components. However, a comprehensive consideration of the strength relevant parameters such as geometry, porosity, hardness and residuals stresses is required to define an optimized choice of particular material and process chain for higher gear strength. In this work, a computational approach is developed, which integrates the numerical modelling of the case hardening and the tooth loading, and the calculation of the load bearing capacity using different fatigue limit criteria. The results of the simulation are evaluated by comparing with available experimental findings.

    DOI:

    https://doi.org/10.59499/EP235765090

  • Authors:

    M. Bemani (1,2,4), S. Parareda (1), D. Casellas (1,3), D. Frómeta (1), A. Mateo (2), R. Das (4), A. Molotnikov (4)

    1- Eurecat, Centre Tecnològic de Catalunya, Metal Digital Manufacturing JRU, 08243 Manresa, Spain

    2- CIEFMA – Department of Materials Science and Engineering, EEBE, Universitat Politècnica de Catalunya, Barcelona-Tech, 08019 Barcelona, Spain

    3- Luleå University of Technology, Division of Mechanics of Solid Materials, 971 87 Luleå, Sweden

    4- School of Engineering, RMIT University, Melbourne 3001, Australia

    Abstract:

    This work addresses the application of such a newly established rapid fatigue testing method to evaluate the fatigue resistance of a Ti6Al4V alloy manufactured by Selective Laser Melting (SLM). The evaluation of fatigue resistance requires expensive and time-consuming tests, which often limit the generation of fatigue data. This is especially relevant for Additive Manufacturing (AM) parts, in which many processing parameters, and their inherent anisotropy, influence fatigue resistance. Accelerated or more straightforward testing procedures would help to develop fatigue-optimized AM parts. Recently, a method based on damage mechanics has been successfully applied to evaluate the fatigue limit in a wide range of steel and aluminum alloy sheets. It gives a good estimation of the fatigue limit in less than one day using a conventional universal testing machine and digital image correlation techniques. A good agreement with the results obtained by the conventional fatigue method is found.

    DOI:

    https://doi.org/10.59499/EP235764573

  • Authors:

    Samuel Lister (1), Simon Graham (1), James Pepper (1), Craig Simpson (1), Nigel Adams (1), Martin Jackson (1)

    1- Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin St., Sheffield S1 3JD, UK

    Abstract:

    Field Assisted Sintering Technology (FAST) is a powder consolidation technique which is growing in popularity due its short, single-step processing cycles. However, as the process matures, more focus is being placed on the production of larger cylindrical samples (both axially and radially). For the process to be economical in production, there is also a drive towards multi-part processing via serial stacking/parallel processing. In both cases, there is the potential for substantial thermal gradients within the sample/stack which could negatively impact part properties. In this work the effect of the thermal gradient (axial and radial), in a stack of eight 120 mm diameter Ti-6Al-4V plates processed in series, has been studied experimentally via microstructural assessment and Vickers hardness measurements. Results were compared with the thermal profile simulated using COMSOL multi-physics modelling software. The successful production of a tall 85 mm height x 120 mm diameter sample is also demonstrated.

    DOI: https://doi.org/10.59499/EP235756151

  • Authors:

    A.V. Shulga

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

    Abstract:

    Rapidly quenched REP-powders produced by melt atomization, evidently, are characterized by the same effect of quenching rate on structure features as in traditional solid state quenching. However, the critical cooling rate, determined in the TTT diagram for melt phase transformation: crystallization is much higher than its value for suppressing austenite transformation in carbon steels. Important features of rapidly quenched powders - high dispersity of dendrites and formation of fine grain struc-ture - determine the precipitation of carbides. Direct nuclear methods of activation autoradiography on carbon, track autoradiography on boron, metallography, SEM, EDX, etc were used for investiga-tion. The structure features including the lattice parameter of a solid solution of rapidly quenched REP powders, HIP PM compacts, products of austenitic stainless steels and their traditional coun-terparts were revealed and analyzed taking into account the role of carbon and boron, precipitation of carbides, borides and effect of non-equilibrium states of investigated materials.

    DOI:

    https://doi.org/10.59499/EP235762945

  • Authors:

    Carl-Magnus Lancelot (1), Andreas Markström (1), Amer Malik (1), Quang Minh Do (1), Johan Jeppsson (1)

    1- Thermo-Calc Software AB, Råsundavägen 18A, 16967 Solna, Sweden

    Abstract:

    Thermo-Calc has spent the last few years developing new models to predict thermophysical material properties to incorporate with CALPHAD-based materials descriptions. This foundation is currently used to extract CALPHAD-based materials data for use in dedicated Finite Element simulation codes, which usually treat material properties in a highly simplified manner. This development has laid the foundation for a completely integrated simulation tool, using the CALPHAD-based descriptions of phase equilibria and physical properties, to simulate the Additive Manufacturing process. The Additive Manufacturing module in the Thermo-Calc software was released this summer, and it gives a unique possibility to address the problem of solidification during AM, where we obtain a unified treatment of both process parameters and chemistry-dependent thermophysical properties when solving the multiphysics problem of a moving heat source that melts and solidifies metal powder. Examples are shown of the AM module applied to different material classes.

    DOI:

    https://doi.org/10.59499/EP235762579

  • Authors:

    Aaron Berger (1), Ulf Ziesing (1), Santiago Benito (1), Sebastian Weber (1)

    1- Chair of Materials Technology, Institute for Materials, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum, Germany

    Abstract:

    PBF-LB/M is the most suitable process for the additive manufacturing with metallic powders when it comes to complex parts with geometrical accuracy. Nevertheless, some unknown variables are present in the process. Especially the thermal conductivity adds a high degree of uncertainty due to the significant influence of the heat flux from the part to the powder bed on the resulting properties of the part. A lack of experimental data addressing the thermophysical properties of powder and a deep understanding of the influences amplifies this problem. This work presents the thermophysical properties of different steel powders commonly used in the PBF-LB/M process using a newly developed powder container. In a quantitative comparative analysis with the corresponding solid materials, it could be shown that chemical composition and microstructure play a subordinate role in the resulting heat conductivity. Instead, the powder size distribution could be identified as the main parameter determining the emerging behavior.

    DOI:

    https://doi.org/10.59499/EP235764023

  • Authors:

    E. Rahimi (1), R. Birley (1), C. Fennell (1)

    1- Materials Processing Institute, UK

    Abstract:

    The reuse of metal powder is an essential step to make the powder bed fusion (PBF) process cost-effective; therefore, understanding the capability of virgin powder is of high importance. Not all the powder is used to make parts in a PBF process. A significant proportion of the un-used powder is collected during de-powdering of the final part. This proportion and a small proportion in the waste chamber can be sieved for reuse. In this research, powder samples were reused until their flowability was below the acceptable level for re-coating. Before every process, morphology, size and flowability were evaluated using the index that was developed in the previous research presented at WorldPM2022 [1]. The index was modified based on the alloy type and reusability aspects and it has been proposed to predict the maximum reusability of virgin powder on the condition that acceptable flowability, morphological distributions and mechanical properties are maintained.

    DOI:

    https://doi.org/10.59499/EP235764680

  • Authors:

    Hosam ElRakayby, KiTae Kim

    Abstract:

    Hot isostatic pressing is a near-net-shape manufacturing process that usually uses a metal container to encapsulate powders then consolidate them to fully dense compacts. Metal containers induce the Mises stress to powder compacts due to the rigidity of the container walls. Thus, anisotropic deformation of powder compacts. This paper investigates the effect of glass container encapsulation on densification and deformation behaviors of 316L stainless steel powder during hot isostatic pressing. Finite element results were compared with measured deformed shape of powder compact after hot isostatic pressing to study the capabilities of glass containers to form near-netshape parts. Glass container showed more homogeneous densification and isotropic deformation of compacts than conventional metal containers.

    DOI:

    https://doi.org/10.59499/EPgfhgsd

  • Authors:

    Alessandra Martucci (1), Giulio Marchese (1,2), Alberta Aversa (1,2), Diego Manfredi (1,2), Sara Biamino (1,2), Daniele Ugues (1,2), Federica Bondioli (1,2), Massimo Messori (1,2), Mariangela Lombardi (1,2), Paolo Fino (1,2)

    1- Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin, Italy

    2- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via G. Giusti 9, 50121 Firenze, Italy

    Abstract:

    The Powder Bed Fusion-Laser Beam is a promising additive-manufacturing process that allows the production of complex-shaped functional components for many applications. However, the layer-by-layer scanning and high cooling rates result in a high thermal gradient (ΔT) and, thus, in thermally induced stresses that could lead to undesirable cracking and delamination phenomena in the final component. A strategy to reduce the ΔT and facilitate a correct heat flow is using support structures. However, the support geometry needs to be optimised, considering that the thermal resistance increases as the support-height increases and the contact cross-section decreases. Furthermore, it is essential to consider the anchoring function of the support structures. Based on these considerations, two geometric indices and a decision support matrix were developed in the present work for a quick and efficient setting of geometric parameters. The robustness of the developed approach was verified on two different alloys: AlSi10Mg and IN625.

    DOI:

    https://doi.org/10.59499/EP235725900

  • Authors:

    Ramin Rahmani (1,2), Javad Karimi (3), Farideh Davoodi (4), João C.C. Abrantes (2), Pedro R. Resende (2), Sérgio I. Lopes (1)

    1- CiTin—Centro de Interface Tecnológico Industrial, 4970-786 Arcos de Valdevez, Portugal

    2- proMetheus—Instituto Politécnico de Viana do Castelo (IPVC), 4900-347 Viana do Castelo, Portugal

    3- BIAS—Bremer Institut für Angewandte Strahltechnik GmbH, Klagenfurter Straße 5, 28359 Bremen, Germany

    4- DMMM—Department of Mechanics, Mathematics and Management, Politecnico di Bari, V.Ie Japigia 182, 70126 Bari, Italy

    Abstract:

    The industry 5.0 revolution prioritizes digital transformation and automation, while also focusing on improving human-machine interface (HMI), improving production and reducing work-related injuries. On the other hand, to tackle the challenge of designing lightweight and complicated structures, new high-tech materials have been developed using combined additive manufacturing (AM) and powder metallurgy (PM) techniques. The futuristic subsections of additive manufacturing (AM) produce composite materials that incorporate both metallic and ceramic components, suitable for a range of applications from art to industrial use. This brief overview examines the key features of the fifth industrial revolution, with particular attention to the selective laser melting (SLM) process. Two specific areas of study include the exploration of an antiviral metal-ceramic composite and also reflective metal fabrication using integrated AM-PM technologies.

    DOI:

    https://doi.org/10.59499/EP235742275

  • Authors:

    Esma Mese (1), Haneen Daoud (1), Wolfgang Hofmann (2), Peter Würtele (2), Uwe Glatzel (1)

    1- Neue Materialien Bayreuth, Germany

    2- Peter Würtele GmbH, Germany

    Abstract:

    The nickel-based superalloy (MAR-M247) is a non-weldable alloy with attractive high-temperature properties. However, it has not been possible to print components using classic additive manufacturing processes. Sinter-based processes enable the production of difficult and non-weldable alloys. But cracking and porosity in printed components is high. Therefore, in this study, highly filled metal filaments of MAR-M247 were used to print specimens using fused filament fabrication (FFF). The microstructure and weight change were analyzed after printing, debinding and sintering by optical and scanning electron microscopy and EDX. The high temperature tensile tests for sintered samples are presented.

    DOI:

    https://doi.org/10.59499/EP235735787

  • Authors:

    T. Lindroos (1), J. Pippuri-Mäkeläinen (1), T. Kinos (1), A. Antikainen (1), T. Riipinen (1), S. Metsä-Kortelainen (1), A. Manninen (1), A. Bertinetti (2), J. O. Odden (3)

    1- VTT Technical Research Centre of Finland Ltd., P.O. Box 1000, FI-02044 VTT, Finland

    2- Gemmate Technologies s.r.l. - CCIAA Torino REA TO-1189884, Italy

    3- Elkem Silicon Product Development AS, Norway

    Abstract:

    Green electrification is vital for the society’s decarbonization. This sets a strong pressure on manufacturers of electric machines to produce items of higher efficiency and, simultaneously, prepare oneself for forecasted supply risks of raw materials. Additive Manufacturing (AM) is seen as enabler to produce components for novel electric machine architectures with designs and performance unattainable with conventional manufacturing. In this study, a permanent magnet (PM) assisted synchronous reluctance motor based on laser powder bed fusion (L-PBF) AM is introduced. Production of soft magnetic powder tailored for L-PBF and optimization of process parameters and further post treatments to achieve good magnetic properties are shown. Characterized magnetic properties are used as input values for motor design where both performance and possibilities of L-PBF are used as design criteria. Permanent Magnet electric motor of the e-scoot is used as reference. The results show that optimized architectures provide high performance with lower PM content.

    DOI:

    https://doi.org/10.59499/EP235763996