Individual Papers

Authors:

Benjamin Delignon (Gränges Powder Metallurgy, France) Hans-Wolfgang Seeliger (Gränges Powder Metallurgy, Germany) Thomas Dickmann (Gränges Powder Metallurgy, Germany) Robert Plesa (Gränges Powder Metallurgy, France)

Abstract:

AlSi alloys are used for lightweight applications requiring high stiffness and low CTE, sometimes in combination with high mechanical properties or wear resistance. Even though these applications are becoming more and more common in the semiconductor and automotive industries, AlSi alloys are crack prone materials, which limits their wider democratisation. In this work we developed three different processing solutions for the production of several AlSi alloys:The production of large size components of AlSi40 by HIP process.The development of LPBF printing parameters for AlSi35 and AlSi25Cu4Mg, targeting mid-size components.The process optimisation to achieve high mechanical properties by combination of sprayforming, extrusion and heat treatment of AlSi25Fe4Ni3CuMgMnCrTi.Various microstructural analyses, mechanical tests, and powder controls were performed in order to define the process parameters enabling industrial and cost-efficient production of these alloys.

DOI:

https://doi.org/10.59499/EP256764899

Authors:

Lars Wimbert (GKN Powder Metallurgy, Germany), René Lindenau (GKN Sinter Metals Engineering GmbH, Germany), Kylan McQuaig (Hoeganaes Corporation, USA)

Abstract:

Most mechanical properties of powder metallurgical (PM) components significantly depend on the part’s density. Considering the higher complexity of modern PM parts and the demand for higher strength with less weight, increased green and sintered densities are required. The development of new advanced lubricants is one key factor for this, providing additives with superior lubricity, clean burn-off and unsophisticated usability. This contribution documents recent developments in lubricant technology with experimental results from lab scale to serial production. The presented lubricant solutions allow powder compaction to higher density levels using lower lubricant additions without the need for heated tooling into a tight temperature range. Especially for complex shaped parts, the broader temperature range helps to keep the lubrication sufficient for tool sections with higher friction, resulting in ejection pressures less than 50% of the values seen for amide waxes.

DOI:

https://doi.org/10.59499/WP225371442

Authors:

Francisco Canillas (1), Nerea Ordas (2), Ernesto Urionabarrenetxea (2), Marcelo Roldan (1), Evelin Cardozo (2), Carlos Bloem (3), Edgar Leon-Gutierrez

1- Ciemat, National Fusion Laboratory, Madrid, Spain

2- Ceit-BRTA and Tecnun (Universidad de Navarra), Donostia-San Sebastián, Spain

3- AIDIMME, Paterna, Spain

Abstract:

CuCrZr is a precipitation-hardenable Cu alloy that combines high thermal conductivity and mechanical strength, along with thermal stability up to 350 °C. In this work we demonstrate the feasibility to obtain dense Cu-(0.6-0.9)Cr-(0.07-0.15)Zr (in wt.%) with densities of 99.5%, high thermal conductivity (>80-85% IACS) and enhanced mechanical strength compared to pure Cu, already in the as-built condition, using Powder Bed Fusion Electron Beam (PBF-EB). Further densification was achieved after HIP. Mechanical characterization showed outstanding results, similar or even superior to those reported in the literature for conventional wrought CuCrZr. Microstructural analysis by SEM, EBSD and TEM revealed a multi-scale hierarchical microstructure of ultra-fine Cr-rich precipitates as well as grain and subgrain boundaries, contributing to the excellent mechanical properties achieved. The microstructural stability of the CuCrZr alloy was evaluated by heat treatments in the range of 350 – 550 °C for up to 1080 hours.

DOI:

https://doi.org/10.59499/EP246300683

Authors:

Ernesto Urionabarrenetxea (1,2), Alejo Avello (1,2), José Manuel Martín (1,2)

1- CEIT-Basque Research and Technology Alliance (BRTA), Manuel Lardizabal 15, 20018 Donostia / San Sebastián, Spain

2- Universidad de Navarra, Tecnun, Manuel Lardizabal 13, 20018 Donostia / San Sebastián, Spain.

Abstract:

Efficient simulation of close-coupled gas atomisation can nowadays be used to improve machine designs and to gain understanding of the complex phenomena taking place in the atomisation process. Two-stage multiphase models can predict particle size distributions by using an Eulerian approach for the primary atomisation and Lagrangian particle tracking for the secondary atomisation. Previous numerical results confirm that these models correctly predict trends of median particle size for varying gas-to-melt mass flow rate ratios, although significant differences between predicted and measured particle size distribution spreads indicate that models need to be improved. In this work, different coupling hypotheses between the primary and secondary atomisation stages are addressed to optimize the model’s capacity to predict the entire particle size distribution. By comparing experimental results with simulations obtained with varying surfaces of particle injections and corresponding boundary conditions, an improved model with better predictive capacity has been obtained.

DOI:

https://doi.org/10.59499/EP235779996

Authors:

Liviu Brabie (Swerim AB, Sweden) Sofia Kazi (Chalmers University of Technology, Sweden) Annika Strondl (Swerim AB, Sweden) Tatiana Fedina (Swerim AB, Sweden) Pelle Mellin (Swerim AB, Sweden) Eduard Hryha (Chalmers University of Technology, Sweden) Fredrik Mikaelsson (Alfa Laval Technologies AB, Sweden)

Abstract:

This study explores the sustainable production of 316L stainless steel powders using atomization with argon (Ar) and nitrogen (N2) gases. The powders were produced at SWERIM’s state-of-the-art VIGA unit, utilizing feedstock from additive manufacturing (AM) residual materials, including defective parts and support structures. By repurposing rest materials, the research aims to minimize the use of virgin raw materials and reduce the carbon footprint associated with powder production. The produced powders were characterized to evaluate their surface properties, including total oxygen content and surface chemistry, powder rheological properties and powder surface chemistry using XPS and HR SEM+EDX. The study examines the influence of atomization gases on powder quality and assesses their potential for reuse in AM processes. The results demonstrate the feasibility of producing high-quality powders from recycled materials, promoting circular economy principles and supporting the development of more sustainable manufacturing practices in the AM industry.

DOI:

https://doi.org/10.59499/EP256766881

Authors:

Rasmus Björk (Quintus Technologies AB, Sweden) James Shipley (Quintus Technologies AB, Sweden) Anders Magnusson (Quintus Technologies AB, Sweden)

Abstract:

Hot isostatic pressing (HIP) has been used to consolidate powder for various industries for many years. It is a well-established production method globally, but newly discussed investments involve larger units than currently in operation. Certain factors are key in developing large HIP systems: enhanced safety, reduced weight and footprint, and safe material handling. This paper will present design considerations of large HIP systems for the powder metallurgy industry. It will also discuss how near-net-shape manufacturing of large components via HIP aids key local industries in sustaining supply chains.

DOI:

https://doi.org/10.59499/EP256766682

Authors:

Giorgio Valsecchi (TAV VACUUM FURNACES, Italy)

Abstract:

High-temperature solution nitriding (HTSN) is a thermochemical treatment that exposes stainless steel to nitrogen gas at specific pressures (below or above atmospheric) and high temperatures (1000°C–1200°C). This process introduces nitrogen into the surface of austenitic, ferritic, and martensitic stainless steels, enhancing their hardness, wear resistance, and corrosion resistance. The HTSN process is followed by a rapid cooling to room temperature, necessary to retain the nitrogen in solid solution without forming chromium nitrides; for that reason, vacuum furnaces dedicated to HTSN need to be specifically designed for such process. A variation of HTSN is also used for Ni-free austenitic stainless steel, such as X15 CrMnMoN17-11-3, which requires a precise amount of nitrogen in solid solution to stabilize the austenitic microstructure at room temperature.This article examines HTSN’s applications for powder metallurgy stainless steel components, detailing process parameters and specialized vacuum furnace designs.

DOI:

https://doi.org/10.59499/EP256767090

Authors:

Jean-Michel Missiaen (Univ. Grenoble Alpes, France), Nicolas Botter (Safran SA, France), Yvan Avenas (Univ. Grenoble Alpes, France), Rabih Khazaka (Safran SA, France)

Abstract:

An assembly for power electronics based on the deposition and pressureless sintering of successive silver layers on an Aluminum Nitride heat sink has been developed. Sintered silver layers act as die attach, current tracks and adhesion layer on the ceramic. This assembly has the advantage to give sintered joints with a high mechanical strength and a high thermal conductivity compared to standard brazing alloys at the highest operating temperature of semiconductor components (200°C). In this paper, aging of the silver tracks and die attach layers is studied. A significant coarsening of the microstructure is observed in confined areas, under the chip and|or far from the external surface, after 200h annealing in air at 200°C, whereas coarsening is essentially inhibited in argon atmosphere. The shear strength and thermal properties of the sintered joint are improved after thermal storage in air. Mechanisms of the microstructural evolution and microstructure-properties relationships are discussed.

DOI:

https://doi.org/10.59499/WP225372071

Authors:

Barbara Rivolta (1), Riccardo Gerosa (1), Davide Panzeri (1), Paolo Veronesi (2)

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

2- Università degli Studi di Modena e Reggio Emilia, Dipartimento di Ingegneria “Enzo Ferrari”, Modena, Italy

Abstract:

Additive manufacturing is nowadays increasingly adopted to produce a large variety of components, especially with complex geometries. A deep investigation and optimization of the mechanical and corrosion performance of the selective laser melted Alloy 625 is extremely useful to support designers in the transition from the conventional to the additive manufacturing technology. Even though the selective laser melting technique is still associated with too high production costs and low productivity to enable a broader expansion, it permits to obtain excellent mechanical and corrosion properties compared to those of the conventionally manufactured alloy. Despite the additively produced material shows outstanding performance already in the as-built condition, aging treatments permit further strength improvement enabling possibility of reducing thicknesses, mass, resources consumption and environmental emissions. However, the balance between the mechanical and corrosion properties is critical and it requires a careful tuning of the heat treatment parameters.

DOI:

https://doi.org/10.59499/EP246281709

Authors:

Ribeiro, Bernardo L.(1,2); Santos, Rúben F. (1,2,3); Barbosa, Maria (2); Sequeiros, Elsa W.(1,2)

1- LAETA/INEGI - Institute of Science and Innovation in Mechanical and Industrial Engineering, Portugal

2- Departamento de Engenharia Metalúrgica e de Materiais da Faculdade de Engenharia da Universidade do Porto, Portugal

3- CCF – Centro de Competências Ferroviário, Portugal

Abstract:

In recent years, High Entropy Refractory Alloys (RHEAs) have been presented as possible alternatives to the state-of-art Ni-based superalloys, due to an outstanding combination of properties under high-temperature service conditions. The MoNbTaW system has been particularly explored due to its considerable high yield strength at temperatures around 1200 °C. Yet, these alloys present a brittle behaviour at room temperature, narrowing their applications. To improve the MoNbTaW properties, in-situ alloying with additions of Vanadium (V) by Direct Energy Deposition (DED) assisted by thermodynamical simulations (CALPHAD) has been explored to accelerate the screening of promising compositions. In this contribution, we present the room temperature microstructural and mechanical characterisation to evaluate the influence of V on the MoNbTaW system.

DOI:

https://doi.org/10.59499/EP235765551

Authors:

Shweta Singh (Indian Institute of Technology Bombay, India), Ankit Gurjar (Indian Institute of Technology Bombay, India), Eshant Bhatia (Indian Institute of Technology Bombay, India), Ishita Krishnatrey (Indian Institute of Technology Bombay, India), Seema Negi (Indian Institute of Technology Bombay, India), Parag Bhargava (Indian Institute of Technology Bombay, India), Rohit Srivastava (Indian Institute of Technology Bombay, India)

Abstract:

The motivation of this work is to improve fracture toughness and incorporate anti-microbial characteristics in alumina ceramics. In this work, alumina-silver composites are prepared by the addition of 2, 5, 10, and 15 wt. % silver nano-flakes. The microstructural analysis is performed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Mechanical properties like flexural strength, fracture toughness, and microhardness are evaluated. Flexural strength is found to decrease with increased silver content while fracture toughness improved significantly. Antibacterial properties are evaluated on E.coli bacteria. All the samples showed antibacterial activity which improved with increased silver content. The present study establishes alumina|silver composite as an antibacterial material with improved fracture toughness which makes it a potential biomaterial for dental and low load-bearing applications.

DOI:

https://doi.org/10.59499/WP225371864

Authors:

Hans-Wolfgang Seeliger (1), Tillmann R. Neu (2), Paul H. Kamm (2), Francisco García-Moreno(2)

1- Gränges Powder Metallurgy GmbH, Germany

2- Institute for Applied Materials, Helmholtz Zentrum Berlin for Materials and Energy, Germany

Abstract:

For the purpose of the application for an on-tank valve, various Al alloy series were produced and tested, to which different contents of up to 0.3 wt% Sc and Zr were added. The hardening curves were plotted for different temperatures and correlated with the corresponding mechanical tests. The alloys were characterized by hardness measurements, tensile tests. By characterizing the materials, transferring them to simulation models and developing design guidelines, the foundations are laid for technology transfer to other applications of these materials. In order to produce these new materials, the Spray Forming process was used on the systems of the Gränges Powder Metallurgy company. This has the advantage that both the metal powder and the solid material for the forged part can be produced in one manufacturing step.

DOI:

https://doi.org/10.59499/EP246278515