Euro PM2023 Proceedings

Authors:

Aamir D. Abid (1), Matt Stone (1), Geof Dusky (1), Bryce D’Alba (1)

1- Retech System LLC

Abstract:

A barrier to the broader adoption of refractory and reactive metal powders (like Titanium and its alloys) is the high cost of AM-suitable powders. Additionally, though companies are producing AM powders using a range of technologies, production rates are slow compared to steel and nickel powder production rates. There is also a limit to the available alloys as conventional processes require the production of high-cost bar or wire feedstock. To address the above-mentioned challenges, Retech has developed an atomization system that would provide a larger production capacity for a range of metal and alloy powders utilizing Plasma Arc Melting (PAM) in combination with gas atomization. Plasma melting allows for the introduction of a broad range of feed materials including revert without incurring the additional cost of processing feed to wire or bar forms. With this flexibility of feed materials, recycling high-value materials becomes an economically viable option. The powders produced on the Plasma Atomizer are spherical with minimal satelliting and low internal porosity. Powder Particle Size Distribution (PSD), morphology, and chemistry is presented in this study and these results are compared to the current state-of-the-art commercial atomized powder technologies.

DOI:

https://doi.org/10.59499/EP235763265

Authors:

Francisco R. Cruz (1), Daniel Gatões (1), Nanci Alves (2), A. Sofia Ramos (1), Teresa Vieira (1)

1- University of Coimbra, CEMMPRE - Centre for Mechanical Engineering, Materials and Processes, Department of Mechanical Engineering, Rua Luís Reis Santos, 3030-788, Coimbra, Portugal

2- ITJ – Internacional Moldes, Lda., Lugar de Embra, 2430-528, Marinha Grande, Portugal

Abstract:

Powder Bed Fusion (PBF) of tool steels as AISI H13 could contribute to a significant improvement of hardness by the presence of nanometric carbides. Moreover, with powder metallurgy new chemical compositions could be in gradient from top to inside 3D object. During additive manufacturing in liquid state, suitable powder mixtures of steel and vanadium &carbon allow the formation of nanocarbides. These elements are selected regarding the exceptional behavior of nanosized vanadium carbides in hardening. The cooling rate in the top surface of melt pool in PBF reaches 106 K/s, inducing carbides, from nanometric to micrometric, as the deepness of the analysis increases. In the present study, vanadium and graphene were added to AISI H13 powder. The possible carbon in excess, dissolved in the matrix, must be similar to the previous carbon percentage of H13 (0.35 %wt.). Nanometric vanadium carbide was distinguished by HRTEM after FIB on top of 3Dobjects.

DOI:

https://doi.org/10.59499/EP235765450

Authors:

araa Qaddah (1&2), Pierre Chapelle (2), Jean Pierre Bellot (2), Julien Jourdan (2), Nicolas Rimbert (3), Agathe Deborde (1), Raphael Hammes (1)

1- IRT M2P, Metz, France

2- Institut Jean Lamour, Université de Lorraine, France

3- LEMTA, Vandœuvre-les-Nancy, France

Abstract:

Gas atomization is the predominant method of powder production for metal additive manufacturing. The EIGA atomizer (Electrode Induction melting Gas Atomization) is a free-fall process used to produce spherical powders, particularly for refractory and high-purity metals such as the titanium alloy Ti-6Al-4V (Ti64). In this process, a swirling supersonic gas jet hits a molten metal stream atomizing it into small droplets through various fragmentation mechanisms. To identify the different fragmentation mechanisms of molten Ti64 within the process, a visualization of the metal atomization by a high-speed video camera is performed in an EIGA tower. The role of the atomization gas pressure on the fragmentation mechanisms and on the final particle size distribution is determined. The mechanisms observed are fiber breakup, bag breakup and Rayleigh breakup for primary fragmentation and bag breakup and shear breakup for secondary fragmentation. Key words: Free-fall atomizer; swirling supersonic gas flow; metal powder; primary fragmentation; secondary fragmentation; high-speed camera.

DOI:

https://doi.org/10.59499/EP235749638

Authors:

Robert Teuber (1), Sebastian Riecker (1), Georg Pöhle (1), Niklas Herzer (1), Thomas Weißgärber (1,2)

1- Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Germany

2- Technische Universität Dresden, Faculty Mechanical Engineering, Institute of Materials Science, Chair Powder Metallurgy, Germany

Abstract:

The work deals with the printing of porous, metallic structures using the MoldJet technology. The MoldJet process is a novel, sinter-based additive manufacturing process, which enables the produc-tion of a wide range of geometries, ranging from small filigree to large-volume metal components without the need of support structures. The high productivity of up to 1600 cm³/h also enables series production of components. These process advantages are now to be exploited in the manufacture of porous structures. The technical limits in terms of porosity, pore size and design freedom are exam-ined. In particular, the different requirements for the component design will be illuminated. Based on different test geometries, the basic possibilities for the production of porous structures using MoldJet are to be demonstrated in an initial study.

DOI:

https://doi.org/10.59499/EP235763906

Authors:

Noluthando B. Mthembu (1), Natasha Sacks (2)

1- Department of Industrial Engineering, Stellenbosch University, Stellenbosch, South Africa

2- DSI-NRF Centre of Excellence in Strong Materials, South Africa

Abstract:

In this study the influence of laser power and scanning speed was investigated on the development of a Ti-6Al-4V alloy reinforced with 10wt%WC to form a metal matrix composite. Response surface methodology was used for both the design of experiments and results analyses. The laser power was varied between 95 and 195W while the scanning speed was varied between 600 and 1000mm/s. Cubic samples were deposited using a continuous alternating meander scanning pattern which was selected after initial optimization of the Ti-6Al-4V alloy. Density, porosity, and Vickers micro-hardness (transverse and longitudinal directions) were measured, while the microstructure was studied using x-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Relationships were established between the measured material properties and the deposition parameters in order to find the optimal deposition parameters for the composite.

DOI:

https://doi.org/10.59499/EP235734093

Authors:

Natasha Sweeney Fort (1), Richard Thackray (1), Hugh Hamilton (2), Gill Thornton (3), Martha Briceno de Gutierrez (2), Xinjiang Hao (3), Andy Fones (2)

1- University of Sheffield, England

2- Johnson Matthey, England

3- Liberty Powder Metals, England

Abstract:

Stainless steels' ability to resist corrosion is improved via cathodic modification. This is achieved through bulk or surface alloying with platinum group metals. However, this approach to the enhancement of stainless steels has yet to find commercial success due to its high costs and the propensity for platinum group metal coatings to debond. This project aims to make cathodic modification more economical by incorporating platinum group metals into stainless steels by powder metallurgical routes. In this study, Ru and Pd doped 316L and 17-4PH stainless steel powders were sintered using field assisted sintering (FAST). Near-full density was attained and elemental segregation was not observed in the sintered samples. This new approach shows potential for reducing the volume of precious metals used in cathodic modification while improving long-term corrosion performance.

DOI:

https://doi.org/10.59499/EP235765422

Authors:

Florian Vollert (1), Johannes Maurath (1)

1- MIMplus Technologies GmbH & Co. KG, Germany

Abstract:

NdFeB magnets show the highest energy products of all known magnetic materials. It is predicted that the demand for this kind of magnets will increase in the following years significantly. However, the required rare earth elements are almost exclusively produced in China. To reduce this dependency the recycling, but also the production of NdFeB magnets in Europe is becoming more and more interesting. In the last few years, MIMplus has developed a process to produce NdFeB magnets from either virgin or recycling material by means of Metal Injection Molding (MIM). In contrast to the conventional production route via press sintering, MIM allows a high level of design freedom (complex shapes and complex magnetization) with comparable magnetic properties. Currently up to magnet grades of N42. The focus on this work is a review of the different challenges that exist for this new production method in order to achieve the state-of-the-art magnetic properties from press sintering.

DOI:

https://doi.org/10.59499/EP235753675

Authors:

Sven Bengtsson (1), Human Gherekhloo (2), Anna Larsson (1)

1- Höganäs AB, Sweden

2- Höganäs Germany GmbH, Germany

Abstract:

The introduction of additive manufacturing in the production of advanced parts for aerospace and similar high-end applications have increased the demands on the powder. To ensure future powder availability for additive manufacturing market, Höganäs has invested in new VIGA atomizer. In this report some of the experience of qualification of AM powders to new modern atomization line are outlined. The new system is easier to operate which should translate into less downtime. Due to improved gas flow in the atomizing tower the new system should improve particle morphology and exhibit less variation in physical properties of the powder. For this reason, physical and chemical properties of the powder were systematically measured in order to compare performance to the older atomizer. Furthermore, a number of prints using the LPBF process were performed, and the mechanical properties of the printed and heat-treated parts were compared.

DOI:

https://doi.org/10.59499/EP235766782

Authors:

Emilio Bassini (1,2,3), Pietro A. Martelli (1,2,3), Serena Lerda (1,2,3), Giulio Marchese (1,2,3), Giacomo Maculotti (4), Gianfranco Genta (4), Maurizio Galetto (4), Sara Biamino, Daniele Ugues (1,2,3)

1- Dipartimento di Scienza Applicata e Tecnologia (DISAT) at Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy)

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

3- Integrated Additive Manufacturing@Polito (IAM) at Politecnico di Torino, Corso Castelfidardo, 51 10138 Torino (Italy)

4- Department of Management and Production Engineering at Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy)

Abstract:

Applying Hot Isostatic Pressing to additively manufactured samples is a key factor in drastically reducing the printing time. In this work, L-PBF IN718 was printed with two different strategies aiming to reduce the leading time drastically. The first consisted of printing a 1 mm dense shell of material, leaving the powders inside completely loosened. The second used two different printing speeds, a slower one for the external shell and a faster one for the core. The two strategies allowed a time saving of 60 and 45 %, respectively. A further time optimization consisted in performing the following HIP process at the same temperature as the annealing treatment to get full densification and the correct microstructure at the same time thanks to a final fast gas quench. The obtained microstructures were assessed morphologically using traditional electronic microscopy and EBSD. Furthermore, the shell-core interface was assessed via micro-indentations.

DOI:

https://doi.org/10.59499/EP235763076

Authors:

M. von Spalden (1), J. Pötschke (1)

1- Fraunhofer IKTS, Germany

Abstract:

In this work, a new approach for preparation of diamond enhanced cemented carbides (DECC) has been evaluated. The main challenge to overcome is the phase transformation of metastable diamond into graphite during sintering. Despite using field assisted sintering to reduce sintering time and temperature as well as a Ni-based binder system instead of Co, graphitisation cannot be fully suppressed. To further reduce the amount of formed graphite, reactive sintering was evaluated to reduce the necessary sintering temperature, due to high sinter activity. Different approaches regarding carbon source and the extent of reactive material were pursued. Reactively sintered DECC could be successfully prepared and did help to understand the kinetics of in-situ WC formation as well as the degradation of diamond during the sintering process. Upon introducing a carbon deficit in a WC-Ni based hardmetal composition the relative density of the resulting DECC was increased at a lower sintering temperature.

DOI:

https://doi.org/10.59499/EP235764988

Authors:

Paolo Veronesi (1), Magdalena Lassinantti Gualtieri (1), Ana C. Feltrin (2), Farid Akhtar (2), Elena Colombini (1)

1- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1 - 41125 Modena, Italy

2- Division of Engineering Materials, Luleå University of Technology, 97187 Luleå, Sweden

Abstract:

Sieve residues from the powder recycling stream in Laser powder bed fusion (L-PBF) processing of Inconel 625 are currently disposed of as hazardous waste, which conflicts with circular economy thinking. Here, the synthesis of metal matrix composites (MMCs) based on carbide- and oxide-strengthening phases finely dispersed in a Multi-Principal Element Alloy (MPEA) matrix was explored as a recycling option for these powders. In particular, mixtures of virgin metal powders and a spent Inconel 625 powder were mechanical alloyed and consolidated by Spark Plasma Sintering (SPS). The process control agent (PCA, ethanol) used during mechanical alloying acted as a source for C and O in the subsequent crystallization of nano-sized carbides and oxides during sintering. By carefully controlling the powder mixture composition, MPEA matrices with different contents of Nb and Mo in the face-centered cubic structure were obtained, as revealed by X-ray Powder diffraction. The bulk samples were further characterized by Scanning Electron Microscopy (SEM) and preliminary mechanical analyses using instrumented indentation. The results showed that spent powder of Inconel 625 was a valuable source of 4d transition metals for the synthesis of MMCs based on a MPEA matrix with enhanced solid solution strengthening and finely dispersed ceramic phases.

DOI:

https://doi.org/10.59499/EP235765342

Authors:

Elena Colombini (1); Magdalena Lassinantti Gualtieri (1); Simone Paggetti (1); Paolo Veronesi (1)

1- Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10/1 - 41125 Modena, Italy

Abstract:

Laser powder bed fusion processing (L-PBF) is an emerging additive manufacturing (AM) technique particularly suitable for the production of parts with complex shapes made of materials with low machinability, such as Ni-based superalloys. Although most of the excess powder following each building cycle can be recycled in successive ones, some solid scrap consisting of large particle aggregates are sieved out from the recycled powder stream and disposed of as hazardous waste. An interesting alternative is recycling for the synthesis of products with high added value such as Multi-Principal Element Alloys (MPEAs). This is explored here for the mechanical synthesis of equimolar CoCrFeNi fcc-structured MPEA doped with 4d transition metals (CoCrFeNiMoxNb0.4x with x=0-0.1) originating from spent powders of Inconel 625. Results from microstructural characterizations and nanoindentation analyses of the powders highlight the feasibility of using spent powders for the mechanical synthesis of fcc MPEAs.

DOI:

https://doi.org/10.59499/EP235765330