Euro PM2023 Proceedings

Authors:

João Teixeira Oliveira de Menezes (1), Federico Matias de la Vega (1), Enrique Mariano Castrodeza (1), Matteo Zanon (2), Tom Pelletiers (3), Riccardo Casati (1)

1- Department of Mechanical Engineering, Politecnico di Milano, Italy

2- Kymera International, Ecka Granules Germany, Germany

3- Kymera International / SCM Metal Products, USA

Abstract:

Binder Jetting of Al alloys can open new scenarios for the additive manufacturing of many alloys that cannot be processed by laser-based printing technologies because of the susceptibility to hot cracking (e.g., 2xxx, 6xxx and 7xxx series alloys). In this study, 6061 Al alloy samples were produced by Binder Jetting. The debinding and sintering parameters were fine-tuned and the tensile and fracture properties of the samples were assessed. Compact tension C(T) fracture specimens were notched in three different crack-plane orientations. Microstructural and fractographic analyses were performed using FE-SEM and LOM. The Al 6061-T6 alloy produced by BJ exhibited very low mechanical anisotropy. The tensile properties are in line with those reported for wrought Al 6061-T6, with a lower elongation at fracture. Brittle fracture occurred in all the crack orientations, with negligible stable crack growth and toughness values corresponding to half of those for hot-extruded Al 6061-T6 along the longitudinal direction.

DOI:

https://doi.org/10.59499/EP235765587

Authors:

W. Limberg (1), T. Ebel (1), R. Willumeit-Römer (1)

1- Institute of Metallic Biomaterials, Helmholtz-Zentrum Hereon, Max-Planck-Straße 1, 21502 Geesthacht, Germany

Abstract:

For this study, tensile test specimens and rectangular shaped fatigue test specimens were produced by MIM, using a mixture of hydride de-hydride (HDH) Ti-6Al-4V powder with high oxygen content (4200 µg/g) and 20% gas atomized Ti-6Al-4V powder with 1600 µg/g oxygen. Due to the oxygen-scavenging effect, the addition of 0.5 wt.-% yttrium powder with a particle size < 45 µm to the powder mixture led to a strong increase of ductility from 4.5% to 13.5%. The results of the fatigue tests, conducted by 4-point bending at room temperature with a load ratio of 0.2 show a totally different behaviour. While the ductility is increasing, the fatigue endurance limit drops from 420 MPa for the pure Ti-6Al-4V down to 350 MPa by the addition of yttrium. This decrease of fatigue strength is caused by the large irregular shaped Y2O3 filled pore clusters, which are forming during sintering. DOI:

https://doi.org/10.59499/EP235763904

Authors:

Antonio Pennacchio (1), Federico Simone Gobber (1), Marco Actis Grande (1)

1- Polytechnic University of Turin – Dept. of Applied Science and Technology (DISAT), C.so Duca degli Abruzzi, 24 10129 Torino, ITALY

Abstract:

Super duplex stainless steels (SDSS) combine the advantages of ferritic and austenitic steels and reach an excellent combination of mechanical and corrosion properties. In addition, high-level mass fractions of chromium, molybdenum, and intermediate nitrogen mass fractions have enabled the higher Pitting Resistance Equivalent Number of SDSS. One of the main goals of the research activity is to evaluate the possible nitrogen variation into the UNS S32760 (X2CrNiMoCuWN25-7-4, AISI F55, 1.4501) super duplex stainless steel powders produced by Vacuum induction melting Inert Gas Atomization (VIGA) (starting from metals scraps and wastes) with two different melt chamber gas atmospheres, Ar or N2. Another study objective concerns the influence of different atomisation gas, Ar or N2 (in combination with the two different melt chamber atmospheres), on powder properties. The identification of the optimal gas process parameters necessary to obtain AISI F55 powders with the correct chemistry composition, especially in terms of nitrogen content, is essential for any subsequent process techniques (L-PBF, 3D printing, MIM, …) to get the best pitting resistance and a good balance in the α ferrite/austenite phase, crucial for the mechanical properties. Therefore, after sieving, the effect of the different gas process parameters on the characteristics of the final powder, in terms of granulometry, morphology, microstructure, chemical composition (also taking into account light elements such as N, O, H, C, and S) and rheology, was investigated.

DOI:

https://doi.org/10.59499/EP235765086

Authors:

Yongkwan Lee (1,2), JaeJin Sim (1,3), SungGue Heo (1,2), Soong Ju Oh (2), MiHye Lee (1), JaeHong Shin (1), Seok-Jun Seo (2), KyoungTae Park (1)

1- Korea Institute for Rare Metals, Korea Institute of Industrial Technology, Incheon 21655, Korea

2- Department of Materials Science and Engineering, Korea University, Seoul 02841, South Korea

3- Department of Advanced Materials Engineering, In-Ha University, Incheon 22212, Korea

Abstract:

Tungsten carbide (WC) is the main raw material of cemented carbide (WC-Co) and is mainly used for cutting tools, wear-resistant tools, and impact-resistant tools because of its excellent high-temperature hardness and high strength. The properties of cemented carbide are greatly affected by the particle size of the tungsten carbide powder, and the development of particle size control technology of the tungsten carbide powder is being actively developed to improve the performance of the tool material. This study evaluated the characteristics according to the amount of reducing agent and carbon input to control the particle size of tungsten carbide powder. The phase composition and morphology evolution of synthesized powders has been examined by X-ray diffraction, scanning electron microscope, and particle size analyser. As a result, WC powder with a particle size of about 200 nm was manufactured under optimized experimental conditions through the control of the reducing agent and carbon content.

DOI:

https://doi.org/10.59499/EP235764653

Authors:

Núria Cinca (1); Riberto Nunes Peres (2); Elena Tarrés (1); Olivier Lavigne (1); Assis Vicente Benedetti (2)

1- Hyperion Materials & Technologies, 08107 Barcelona, Spain

2- São Paulo State University—UNESP, Instituto de Química, Araraquara 14800-060, SP, Brazil

Abstract:

The effect of the WC grain size on the corrosion resistance of cemented carbides is not well established in the literature. In this study, the electrochemical behaviour of WC-12wt.%Co hard materials with various starting grain sizes (ultrafine, fine, and medium) were evaluated in aerated 3.5 wt.% NaCl media as well as 0.1M NaOH and 0.1M H2SO4, by means of electrochemical techniques (Electrochemical Impedance Spectroscopy, EIS, and polarization scans). Results showed that the corrosion resistance of the material is slightly dependant on the WC grain size. Based on EIS results, the corrosion resistance of the material in acidic media slightly increases when decreasing the WC grain size, while an inverse trend is observed in alkaline media. This is due to the inherent heterogeneity of the two-phase nature of these materials.

DOI:

https://doi.org/10.59499/EP235756856

Authors:

Marco Mariani (1), Luigi Montipò (1), Nora Lecis (1)

1- Department of Mechanical Engineering, Politecnico di Milano, Via La Masa 1, 20156, Milano, Italy

Abstract:

Binder jetting is a sinter-based technique that allows the production of application-oriented designs with a reduced consumption of raw materials. The employment of powders from scrap metal recycling would minimise the lifecycle impact of the process. In our work, gas atomised powders tailored for binder jetting are compared to a feedstock obtained by recycling of 316L waste. The morphological features of particles, especially sphericity and size distribution, are measured by granulometry and scanning electron microscopy. Printed components are studied at the green and sintered state to observe the influence of each feedstock and the comparative analyses on density and final microstructures (residual porosity, grain size and phases distribution) allows to determine which are the most beneficial properties of the powders. CALPHAD modelling highlights the feedstock chemical composition effects on densification mechanisms: Ni and C content are responsible for δ phase formation and solidus temperature, thus affecting diffusive processes during sintering.

DOI:

https://doi.org/10.59499/EP235764265

Authors:

J. B. Lee (1), J. Y Jeong (1), B. G. Lim (2), H. G. Jeong (1)

1- Korea Institute of Industrial Technology, Republic of Korea

2- AMOTECH co. ltd., Republic of Korea

Abstract:

Commercial hydrothermally synthesized BaTiO3 powder with a cubic structure was annealed in a temperature range of ~900 ℃, and the cubic-tetragonal structure transition and microstructure evolution of the powder were investigated in relation to the sintering processes. The BaTiO3 powder used had a cubic structure below an annealing temperature of 900 ℃ and a tetragonal structure above 900 ℃. The pre-annealed powders with a cubic structure were transformed into powders with a tetragonal structure by sintering above 900 ℃, irrespective of the environment.

DOI:

https://doi.org/10.59499/EP235762595

Authors:

García de la Cruz Lucía (1), Lagos Miguel (2), Alvaredo Paula (1), Torralba José Manuel (1,3), Campos Mónica (1)

1- Universidad Carlos III de Madrid, Leganés, Spain

2- TECNALIA, Donostia-San Sebastián, Spain

3- IMDEA Materials Institute, Madrid, Spain

Abstract:

Electrical resistance sintering (ERS) is an ultrafast sintering process that uses high current densities and pressure to consolidate samples in a few seconds. These conditions enable the consolidation of powder partially retaining its original characteristics. Such characteristics can be modified by low energy mechanical milling, deforming superficially the powder while retaining its spherical shape. CoCrMo alloy is widely used for biomedical applications and requires a good combination of strength and ductility, which can be achieved with customized microstructure that features the proper phase distribution and grain size. This research investigates the use of ERS as a promising tool to fabricate CoCrMo samples from powder processed at different milling times, for exceptional mechanical properties. Microstructures are studied by means of SEM/EBSD and XRD and mechanical properties evaluated in terms of hardness.

DOI:

https://doi.org/10.59499/EP235764663

Authors:

G.P. De Gaudenzi (1); S. Tedeschi (1); F. Pirone (1); D. Ruggiero (1); F. Tavola (2); and B. Bozzini (2)

1-F.I.L.M.S. S.p.A., Italy

2-Dept. of Energy, Politecnico di Milano, Italy

Abstract:

Circular use of the main hardmetal constituents is mandatory for European industrial economy. Over the past 20 years some recovery processes have been integrated in the extractive metallurgy or directly in the hardmetal production processes. Among attempted recovery routes, electrochemical methods have been studied since the ‘70’s, although they never climbed to the level of an industrial process. In this work, we present the crucial electrochemical knowledge-base that has enabled the definition of an electrochemical demolition process, claiming to overcome the productivity barrier that, so far, has hindered the industrial application of electrochemical scrap treatments. In particular, in this contribution, we concentrate on the systematic investigation of the electrochemical response of HM in the pseudopassive and transpassive condition, an appropriate sequence of which is adopted in our electrochemical demolition process. As a worst-case benchmark, this study revolves around a representative series of corrosion-resistant grades.

DOI:

https://doi.org/10.59499/EP235763766

Authors:

Karl-Heinz Leitz (1), Bernhard Valentini (1)

1- PLANSEE SE, 6600 Reutte, Austria

Abstract:

High temperature vacuum furnaces for heat treatment typically have operation powers of several hundred kilowatts. They are generally equipped with a fast-cooling system that has to assure that cooling rates, required for certain heat treatment processes, are uniformly met in the whole load. In this contribution thermo-electric and thermo-fluid dynamic analyses of a high temperature vacuum furnace with a refractory metal hot zone are applied to show potentials for energy savings without losing cooling efficiency. The simulation results are validated by experimental data. The results show that an optimization of the gas system allows energy savings of up to 20 % without losing cooling efficiency.

DOI:

https://doi.org/10.59499/EP235764058

Authors:

G. Walther (1), J. Trapp (1), T. Weißgärber (1,2)

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

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

Abstract:

Sintered friction materials are used in particular for high performance applications due to their excellent temperature stability. Increasingly, new regulations regarding sustainability and environmental compatibility require innovative materials. In the USA, only brake pads with less than 0.5 percent may be sold by 2025 due to toxic abrasion. In addition, the new Euro 7 standard also imposes stricter limitations on non-exhaust particulate emissions. In this paper, material solutions for iron-based sintered linings for motorcycle brakes and synchronizer rings are discussed as an example of how to replace copper-based systems without losses in performance. Furthermore, the development of an aluminum composite brake disc is presented. These new brake discs use a particle-reinforced aluminum friction ring, which ensures an almost complete avoidance of the abrasion and, therefore, particle emission. Besides, the aluminum-based brake discs allow for lighter and more sustainable cars, e.g. by a 50 % reduction of the brake system’s weight.

DOI:

https://doi.org/10.59499/EP235764215

Authors:

Tom Andersson (1); Matti Lindroos (2); Abhishek Biswas (1); Tomi Suhonen (1); Supriya Nandy (1); Anssi Laukkanen (1); Juha Lagerbom (2); Tomi Lindroos (2); Pilar Rey Rodriguez (2)

1- VTT Technical Research Centre of Finland, Espoo, Finland

2- VTT Technical Research Centre of Finland, Tampere, Finland

3- AIMEN Centro Tecnológico, Porriño,Spain

Abstract:

We present a workflow and model prediction of a behaviour for an alloy designed for an application, which require high strength materials, with multiscale material modelling method. Material is designed to have suitable phase composition with CALPHAD-method and neural network tool that is taught with the empirical high entropy alloy design criteria. The material is estimated to be two phase (FCC-BCC) structure in as-build condition and after heat treatment gamma-gamma' and BCC-B2 structure. Designed alloy is atomized and test specimens are produced with direct energy deposition method. Specimens are heat-treated to get the desired phase composition. Tensile tests and micromechanical characterization are combined with simulation tools to create a micromechanical model that is used for mechanical property and performance simulations. A workflow to combine the different methods in order to assess the performance of the material.

DOI:

https://doi.org/10.59499/EP235764634