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Authors:

Ariadna Marin (1), Rocío Muñoz Moreno (1), María Teresa Pérez-Prado (2), Sergi Bafaluy Ojea (2), Federico Sket (2)

1- HP Printing and Computing Solutions S.L., Spain

2- IMDEA Materials Institute, Eric Kandel, Spain

Abstract:

3D Metal Binder Jetting is currently disrupting manufacturing and accelerating mass production of 3D-printed parts. Its excellent balance between part quality and productivity rates is founded on powerful R&D investigations and metrics development to support applications for industrial cases. In this study, the technical physics description of the binder jet fundamentals and its role on parts consolidation will be explained. In particular, the focus will be on describing novel metrics of green parts microstructure obtained by scanning electron microscope (SEM) and X-ray computed tomography (XCT) as binder and porosity local fractions and their spatial distributions. These unique metrics will be evaluated for different powders and R&D print modes. The use of this set of metrics to support print mode development and materials integration, as a predictive and more sustainable method will be discussed.

DOI:

https://doi.org/10.59499/EP246280667

Authors:

Aditya Gopaluni (1), Pasi Puukko (1), Atte Antikainen (1), Hepo-oja Lotta (1), Joni Reijonen (1)

1- VTT Technical Research Centre of Finland, Finland 02044

Abstract:

Additive Manufacturing (AM) is considered as one of the most suitable methods for building parts with complex designs. AM is described as an efficient and sustainable manufacturing method, when compared to the traditional manufacturing methods. To understand the credibility of AM as a sustainable process, a study of the life cycle assessment (LCA) was conducted for PBF-LB, BJT-M and CNC machining for manufacturing of an impeller. The LCA calculations were made for different scenarios with respect to feedstock. It was observed that BJT-M had the largest CO2 footprint compared to PBF-LB, followed by CNC machining. It was concluded that the BJT footprint is highest owing to the extra steps involved in making the part user ready, mainly sintering. This study has been conducted as natural extension of a previous study conducted on LCI of PBF-LB and CNC processes and approaches the LCA from the point of view of raw material.

DOI:

https://doi.org/10.59499/EP246275974

Authors:

S. Sauceda (1,2), S. Lascano (3), C. Arévalo (2), I. Montealegre (2), E.M. Pérez-Soriano (2), P. Pedrosa (2), A. Machuca (3), R. Chavez (3), N. Araya (1)

1- Departamento de Ingeniería de Materiales, Universidad de Concepción, Chile.

2- Departamento de Ingeniería y Ciencia de los Materiales y del Transporte, Escuela Politécnica Superior, Universidad de Sevilla, Spain.

3- Departamento de Ingeniería Mecánica, Universidad Técnica Federico Santa María, Chile.

Abstract:

Applications such as high-power contacts or nuclear fusion reactors frequently rely on W-Cu composites when demanding exceptional electrical and thermal conductivity under extreme conditions. Powder metallurgy serves to create this type of material with different melting points. However, there is a discussion in the literature about the most suitable powder metallurgy techniques. Spark Plasma Sintering (SPS) and Rapid Sintering Process (RSP) make it possible to produce materials within minutes and at lower temperatures on an industrial scale. This study undertakes a comparative analysis of two different sintering techniques at 600°C while varying the pressure and sintering time for W-Cu samples containing 25% and 75%wt. of W. Results show that it is possible to sinter composite W-Cu at 600°C. The material's density, hardness, and microstructure are significantly affected by sintering time. Furthermore, RSP tends to generate higher densities, hardness and Young's modulus.

DOI:

https://doi.org/10.59499/EP246280921

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:

Felix Radtke (1), Markus Mirz (2), Klaus Dollmeier (3), Simone Herzog (1,2), Christoph Broeckmann (1,2)

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

2- Institute for Materials Engineering in Mechanical Engineering, Aachen, Germany

3- Georgsmarienhütte Holding GmbH, Georgsmarienhütte, Germany

Abstract:

Austenitic high nitrogen steels (HNS) are the material of choice in the aerospace, medical, and electronics industry due to their unique combination of high strength, ductility and corrosion resistance. The standard manufacturing route of HNS parts comprises of pressure electroslag remelting and machining by turning or milling. In this study, the Powder Bed Fusion – Laser Beam Metal (PBF-LB/M) process was developed for the austenitic HNS grade X13CrMnMoN18-14-3. Analysis of key factors, such as porosity and manganese content, led to an optimized process window. Solution annealing ensured a fully austenitic transformation of an unintended duplex structure on cost of the fine as-built microstructure. Metallurgical analysis allowed the discussion of the effects of nitrogen content and microstructure on strength, hardness and toughness. The study achieved the desired material properties and contributes to the development of improved materials for the PBF-LB/M process.

DOI:

https://doi.org/10.59499/EP246278588

Authors:

Volker Piotter (1), Alexander Klein (1), Klaus Plewa (1), Heinz Walter (1)

1- Karlsruhe Institute of Technology (KIT), Institute for Applied Materials (IAM-WK), Eggenstein-Leopoldshafen, Germany

Abstract:

Although key words like digital twin, digitalization, big data etc. are dominating our ideas for the future world of manufacturing there is still the demand for particular determination of real material parameters. Simulation of Powder Injection Moulding (PIM) makes no exception, however, due to the high degree of particle filling even marginal changes of the initial values may lead to thorough differences of the results. It could be demonstrated that accidently irrelevant improvements in pvt-data determination resulted in significantly higher accurate predictions. The influence of Bagley-correction as usually applied for polymer material characterization does not lead to better simulation reliability in case of highly filled PIM feedstocks.

DOI:

https://doi.org/10.59499/EP246281624