Individual Papers

Authors:

Leo Monier (SIMap, France), Arthur Despres (SIMap, France), Jean-Jacques Blandin (SIMap, France), Muriel Veron (SIMap, France)

Abstract:

Additive manufacturing is an opportunity for the energy field to produce sophisticated geometries. However, there are still several roadblocks to its use to make a wide variety of parts. One needs to demonstrate that parts produced with conventional processing routes can be substituted by parts fabricated by additive manufacturing. Parts made of 316L stainless steels have been fabricated using two different powder batches while keeping the exact same processing conditions. The nominal composition of the two initial powder batches differs slightly, but it led to very different microstructures. Powder batch 2 leads to a finer grain structure that goes along with texture randomization. The underlying mechanism responsible for grain refinement and texture randomization is discussed and can be considered as an alloy design strategy in the framework of additive manufacturing.

DOI:

https://doi.org/10.59499/WP225368071

Authors:

Berend Denkena (Leibniz Universität Hannover, Germany), Benjamin Bergmann (Leibniz Universität Hannover, Germany)

Abstract:

Addition of carbide-forming elements to metal-bonded diamond grinding wheels can increase the grain retention through carbide formation at the grain-bond interface. In order to investigate the effect of chromium addition, bronze-bonded diamond grinding wheels were fabricated through field assisted sintering technology. At a sintering temperature of 720°C no carbide formation within the interface of diamond and bronze-bond was observable. The chromium particles remain unreacted und evenly distributed within the grinding layer after sintering, resulting in no significant increase in grain retention forces. Nevertheless, the chromium addition leads to a decrease of ductility of the bond, resulting in a grinding wheel surface topography were diamonds are more exposed and the bond is further recessed after machining. The thus emerging higher grain protrusion results in an improved grinding behaviour with a decrease of near 100% in process forces and increase of 446 % in G-Ratio.

DOI:

https://doi.org/10.59499/WP225370611

Authors:

Jakub Szalatkiewicz (Phoenix Surowce Sp. z o.o., Poland) Roman Szewczyk (Warsaw University of Technology, Poland) Marzena Szałatkiewicz (Phoenix Surowce Sp. z o.o., Poland) Adrian Radoń (Łukasiewicz Research Network – Institute for Non Ferrous Metals, Poland) Anna Czech (Łukasiewicz Research Network – Institute for Non Ferrous Metals, Poland) Wojciech Rogalski (Phoenix Surowce Sp. z o.o., Poland) Ivan Patapenka (Phoenix Surowce Sp. z o.o., Poland) Marcin Śladowski (Phoenix Surowce Sp. z o.o., Poland) Piotr Gazda (Warsaw University of Technology, Poland) Michał Nowicki (Warsaw University of Technology, Poland) Aleksandra Kolano-Burian (Łukasiewicz Research Network – Institute for Non Ferrous Metals, Poland)

Abstract:

The article presents the potential and quality of Critical Raw Materials (CRM), concerning powders from NdFeB magnets composed of Rare Earth Elements (REE) recovered by a tailored robotized disassembly system backed up by Artificial Intelligence and Machine Vision. The technology focuses on processing the end-of-life Hard Disk Drives (HDDs) from Waste of Electric and Electronic Equipment (WEEE). It allows the recovery of high-quality metals and rare earth elements magnets. From the HDDs, NdFeB magnet powder was generated by a hydrogenation process for its use in new magnet manufacturing, ie. by sintering or 3D printing. The composition of recovered hard disk drive magnet powder and its characterization are presented, as well as the description of the mass balance and recycling process. Next to recovery of critical raw materials, secure and environmentally friendly data destruction with its carriers, of the end-of-life computer hard disk drives, is presented and described. The presented solution opens a new approach to robotized, highly efficient recycling of tailored waste of electric and electronic devices. Finally, the article confirms the importance

DOI:

https://doi.org/10.59499/EP256779721

Authors:

Karl Burkamp (1), Tobias Hajeck (1), Paul Beiss (1), Alexander Bezold (1), Christoph Broeckmann (1)

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

Abstract:

This short study tackles macro hardness conversion challenges in sintered steels, underscoring the inadequacies of standard methods suited for fully dense steels. By examining a range of sintered steel samples across Rockwell, Vickers, and Brinell hardness scales, it reveals significant measurement discrepancies. In response, the study introduces bespoke conversion functions for sintered steels, aimed at ensuring precise and dependable hardness scale translations. This approach not only illuminates the distinct hardness characteristics of sintered steels but also offers vital tools for enhancing data interpretability and industry-wide comparability. This short study stands out for its practical implications, promising to improve material evaluation reliability through better hardness data comparisons, benefiting engineers, metallurgists, and researchers focused on sintered steels.

DOI:

https://doi.org/10.59499/EP246281408

Authors:

Sasan Amirabdollahian (University of Trento, Italy), Maryam Eslami (Ohio University, USA), Matteo Perini (ProM Facility of Trentino Sviluppo, Italy), Alberto Molinari (University of Trento, Italy)

Abstract:

Laser-directed energy deposition (L-DED) is one of the most practiced additive manufacturing (AM) methods that provide opportunities for the production of parts as well as repair and cladding. AISI 415 Martensitic stainless steel demonstrates high mechanical properties, excellent toughness, and weldability with a wide range of applications. In the current work, crack-free and full-dense parts were deposited after developing proper processing parameters. As-built (AB) microstructure comprised lath martensite with a microhardness of 400HV. The effect of two different heat treatment scenarios of direct tempering of the as-built part (DT) and austenitization and quenching prior to tempering (QT) on the microstructure and hardness were investigated. The tempering curves for the two scenarios were similar, demonstrating a hardening peak at 450°C, while DT samples possessed slightly higher hardness due to the finer martensite substructure. Polarization tests revealed AM sample demonstrates 110 mV higher pitting potential compared to the conventional.

DOI:

https://doi.org/10.59499/WP225372183

Authors:

Yasin M. El Sayed (1), Alessandro Colaneri (1), Stefano Lionetti (1), Leonardo Fransesini (1), Chiara Guerrera (1), Oriana Tassa (1)

1- RINA Consulting – Centro Sviluppo Materiali, Italy

Abstract:

The purpose of this work was to develop a heat treatment to be performed on Additive Manufacturing (AM) 3D printed samples made of M300 steel to improve their mechanical properties, tailoring the as-built microstructure with the minimization of material defects like voids, porosity, micro-cracks, and variations in material structure. Different solution and ageing heat treatments were performed on samples printed via the Selective Laser Melting (SLM) technique, testing different durations, temperatures, and trends in the heating and cooling phases. The samples were microscopically analysed and mechanically tested with tensile tests and hardness (HV10). The results were compared with as-is samples showing improved mechanical properties, meaning an effective heat treatment was applied.

DOI:

https://doi.org/10.59499/EP246281343

Authors:

Ilídio Costa (Faculty of Engineering of the University of Porto, Portugal) Bernardo L. Ribeiro (Faculty of Engineering of the University of Porto, Portugal) Dinis Carneiro (Faculty of Engineering of the University of Porto, Portugal) Bruno Cunha (Faculty of Engineering of the University of Porto, Portugal) José Monteiro (Faculty of Engineering of the University of Porto, Portugal) Elsa W. Sequeiros (Faculty of Engineering of the University of Porto, Portugal)

Abstract:

Inconel 718 (INC718) components manufactured by Directed Energy Deposition (DED) require optimized post-processing heat treatments due to their distinct solidification conditions and resultant microstructures compared to conventional manufacturing methods. While extensive research exists on heat treatments for wrought and powder bed fusion-produced INC718, limited studies address DED-specific heat treatment optimisation. This study and explores the effects of various solutions and ageing heat treatments on DED-manufactured INC718 through samples' mechanical and microstructural characterisation by using OM, SEM|EDS|EBSD, and Vickers hardness testing. The as-deposited material exhibited significant niobium segregation and Laves phase formation in interdendritic regions. Solution treatment at 1150°C proved more effective at dissolving Laves phase compared to conventional 980°C treatment. Modified solution and ageing parameters (1150°C|1h + 720°C|8h + 620°C|8h) resulted in significantly improved hardness (491±13 HV0.2) compared to standard heat treatments. These findings demonstrate the necessity of developing specific heat treatment protocols for DED-manufactured INC718 to achieve optimal properties.

DOI:

https://doi.org/10.59499/EP256767779

Authors:

Srinivasan Suresh (1), Gillham Joe (1), Marshall M. Jessica (1)

1- University of Warwick, Coventry, United Kingdom

Abstract:

Development of high-density radiation shielding is one of the key aspects in deploying new nuclear reactors (Gen IV fission and fusion) to decarbonize global energy production. The current candidate materials based on refractory metals and tungsten (W)-based alloys do not yet meet the engineering requirements of a practical power generating compact spherical tokamak (cST) reactor. Radiation shielding materials must fulfil not only the materials challenges and radiological safety requirements, but also the regulatory requirements in the case of accidents. Cemented tungsten carbide (cWC)-reactive sintered boride (RSB) composites are promising candidate for compact radiation-dense nuclear armour. This review presents the synthesis and characterization of cWC-RSB materials under various processing conditions for nuclear radiation shielding. This includes simulation of compositions and synthesis parameters of cWC-RSB composites using the CALPHAD method. The radiation attenuation capabilities, radiation damage and mechanical properties of cWC-RSP composites under various scenario, simulations and conditions are discussed.

DOI:

https://doi.org/10.59499/EP246283660

Authors:

A. Meza (1), A. Alonso (1,2), J.M. Torralba (1,2), L. García de la Cruz (2)

1- IMDEA Materials Institute, Spain

2- Universidad Carlos III de Madrid, Spain

Abstract:

High entropy alloys (HEAs) are researched due to their distinct microstructures and impressive mechanical performance, which are achieved by combining multiple principal elements in nearly equal ratios. However, the inclusion of multiple elements poses challenges in HEAs fabrication by PM routes due to the high cost of pure elemental powders and the absence of readily available prealloyed HEAs compositions. Employing commodity powders such as Ni625, CoCrF75, or 316L has emerged as a viable approach, reducing manufacturing expenses and facilitating HEAs development. In this study, a fixed fraction of the aforementioned powders was used to produce HEAs using metal injection moulding (MIM). The main goal is to achieve a single FCC HEA phase exhibiting exceptional mechanical properties. To this aim, the metallic powder was mixed with high-density polyethylene and paraffin wax as binder system, and the optimal powder loading was investigated. After injection, debinding and sintering stages were optimised while microstructural and mechanical assessments were conducted on the final samples.

DOI:

https://doi.org/10.59499/EP246278267

Authors:

Maria de Nicolás-Morillas (1), Alberto Meza (1,2), Sivagnana Venkatesh Kumaran (1), Adrian Cotobal (1), Diego Iriarte (1), Daniel Martín (1), Srdjan Milenkovic (1), José Manuel Torralba (1,2)

1- Sustainable Powder Technologies – IMDEA Materials Institute, Tecnogetafe, Madrid, Spain

2- GTP – Universidad Carlos III de Madrid, Madrid, Spain

Abstract:

The battle against climate change requires alternative and renewable energy supplies, where hydrogen has emerged as an excellent candidate. Its most cost-effective storage is in its gaseous form, with the use of metallic pressure vessels. Compared to traditional compositions, such as steels, High Entropy Alloys (HEAs) arise as promising materials with stable phases resistant to the phenomenon of hydrogen embrittlement. In this investigation, two HEA compositions have been studied: AlCoCrFeNi2.1, a biphasic-eutectic (BCC+FCC) alloy, and CoCrFeNiMo2.1, a monophasic (FCC) one. They were processed via Laser Powder Bed Fusion (LPBF). Moreover, an annealing treatment was applied to LPBF samples, seeking to study the variation of the microstructural scenario and its effect in the mechanical behaviour of the material in a hydrogen-pressurized atmosphere. In doing so, as-built and annealed samples were subjected to three-point bending tests in a range of 0-280 bar of H2, showing the superior behaviour of the monophasic-FCC HEA composition.

DOI:

https://doi.org/10.59499/EP246278417

Authors:

Zahid Anwer (1); Jef Vleugels (1); Shuigen Huang (1)

1- Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, box 2450 - 3001, Leuven, Belgium

Abstract:

Fully dense high entropy carbide (Nb0.2Ta0.2V0.2Ti0.2W0.2)C - 10.64 wt.% Ni-based cermets were prepared by in-situ carbothermal reduction of mixtures of transition metal oxides from Group IV, V and VIB by a one-step reactive sintering technique. The molar ratio of metal oxides and graphite in the starting powder mixtures was varied and the evolution of the microstructure, grain size and morphology of the HEC phase was studied in detail. The in-situ carbothermal reduction of oxides resulted in a high entropy carbide phase with a homogeneous backscattered electron atomic number contrast with an extremely faint core-rim structure. This study demonstrates a facile and cost-effective alternative synthesis approach to prepare chemically complex high entropy carbide based cermets in a one-step pressureless sintering cycle. The two-phase HEC-Ni cermets exhibits an excellent hardness around 16.5 GPa and an acceptable fracture toughness around 7.5 MPa.m1/2.

DOI:

https://doi.org/10.59499/EP235763795

Authors:

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

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

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

Abstract:

Additivated powders for powder bed fusion – laser beam (PBF-LB/M) process allow for innovative materials, which cannot be produced by conventional manufacturing techniques. In this study, Si3N4 powder is added to an austenitic steel powder for the manufacturing of high nitrogen steels (HNS). Therefore, two different types of additivation are investigated using tumbling mixers with and without grinding balls. Variations in the oxygen content and particle size distribution of the ceramic powder are analyzed to gain knowledge regarding influences on the rheological and reflective properties of the additivated powder. The flowability and packing density are determined as a function of humidity and drying parameters of the powder. The first samples of the investigated powders were processed by PBF LB/M. Microscopic investigation reveals new insights into the melting mechanisms of metal/ceramic mixtures. An analysis of the residual powder gives first indications regarding recyclability.

DOI:

https://doi.org/10.59499/EP235764243