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Authors:

Lucas Vogel (1,2), Qaiser Ali Khan (2), Andreas Baum (2), Martina Zimmermann (3,4), Carlo Burkhardt (1)

1- Institut für strategische Technologie- und Edelmetalle, Hochschule Pforzheim, Germany

2- MetShape GmbH, Germany

3- Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS Dresden, Germany

4- Institut für Werkstoffwissenschaft, Technische Universität Dresden, Germany

Abstract:

The lithography-based metal manufacturing (LMM) process is a novel additive manufacturing technique that enables the sinter-based manufacturing of metal parts with high dimensional precision and exceptional surface quality. To effectively apply this technology, comprehending the relationship between mechanical properties and printing orientation is imperative. Given the relative novelty of this technology, our study seeks to explore the influence of manufacturing orientation on both the mechanical properties and shrinkage behaviour of stainless steel 17-4PH. In most additive manufacturing technologies typical variations in mechanical properties is observed in every axis, our investigation focuses on assessing the tensile properties of the material in all orientations. Tensile bars are fabricated accordingly and evaluated in terms of density and dimensions as both green and sintered components. Subsequent to the sintering process, an in-depth analysis of mechanical properties and microstructure is conducted to elucidate the inherent correlations between the technology and material.

DOI:

https://doi.org/10.59499/EP246278376

Authors:

Prathviraj Upadhyaya (South Eastern Applied Materials (SEAM) Research Centre, Ireland), Sinéad M. Uí Mhurchadha (Waterford Institute of Technology, Ireland), Tríona Kennedy (Stryker European Operations Limited, Ireland), Ramesh Raghavendra (South Eastern Applied Materials (SEAM) Research Centre, Ireland)

Abstract:

WE43 magnesium alloy is a low density, biocompatible material that has been identified as a viable option for temporary orthopaedic implants due to its favourable mechanical and biodegradation properties. This bioresorbable material eliminates the requirement for an invasive second surgery to remove a traditional bioinert temporary implant after the bone has regenerated. Additive manufacturing allows for complex structures with biomimicry features to be produced. However, the additive manufacturing of Magnesium and its alloys is not a trivial task due to challenges associated with the processability of Magnesium. This paper presents a methodology to additively manufacture WE43 components. Furthermore, an additively manufactured demonstrator orthopaedic fixture is presented and the microstructure evolved within the part and the resulting mechanical and corrosion properties are characterised. This research is aimed towards the development of additively manufactured, bioresorbable orthopaedic implants, with potential to improve clinical outcomes for patients.

DOI:

https://doi.org/10.59499/WP225372016

Authors:

Elsa Sequeiros (FEUP, Portugal) Ana Figueiredo (FEUP, Portugal) Regina Coelho (FEUP, Portugal) Rui Ribeiro (FEUP, Portugal) Jose Costa (FEUP, Portugal)

Abstract:

This study aimed to characterize a 316L stainless steel powder and a component produced from the same powder batch using the Laser Powder Bed Fusion (LPBF) process. SEM and EDS analyses, apparent density, tapped density, and pycnometric tests were conducted, alongside DSC and XRD analyses. The powders exhibited predominantly spherical morphology, with some variation in particle size and surface oxidation due to recycling and improper storage. Particle size distribution analysis using a Mastersizer 3000 revealed a fine powder fraction, with a median particle size (Dv50) of approximately 2?µm, significantly below the typical LPBF range. The crystalline structure of the powder was predominantly austenitic, with minor peaks that could correspond to ferrite or martensite. The component exhibited hardness values between 230 and 260 HV0.1, with a homogeneous distribution along both build and transverse directions. These results highlight the critical importance of powder condition monitoring for maintaining LPBF component quality.

DOI:

https://doi.org/10.59499/EP256768115

Authors:

Gian Pietro De Gaudenzi (OMCD Tek Hub SpA, Italy) Mattia Garabelli (OMCD Tek Hub SpA, Italy) Fransisca Pirone (OMCD Tek Hub SpA, Italy) Sandra Tedeschi (OMCD Tek Hub SpA, Italy)

Abstract:

In the pursuit of developing alternative hardmetal systems to replace WC-Co grades for wear applications, ?-carbides and Functionally Graded HardMetals have garnered significant attention. This study focuses on characterizing a specific type of Functionally Graded HardMetals, more accurately defined as Functionally Layered HardMetals. The investigation examines the effects of coupling layers composed of different carbides and binder compositions. Two ?-carbides, niobium carbide and titanium carbide, were studied both in combination with each other and with tungsten carbide. Microstructural analyses of stacked samples revealed the formation of mixed carbide layers at the interfaces and the mutual migration of small amounts of refractory carbides. The study evaluates the impact of these compositional gradients on mechanical properties and the interaction of the coupled systems with oxidizing environments at room and elevated temperatures. These findings provide valuable insights for the development of layered hardmetal systems composed of various carbides, tailored to achieve functional objectives.

DOI:

https://doi.org/10.59499/EP256768126

Authors:

Ilidio Costa (Faculty of Engineering of the University of Porto, Portugal) Diogo Mota (Faculty of Engineering of the University of Porto, Portugal) Mariana Maia (Hypermetal, Lda., Portugal) Afonso Nogueira (Hypermetal, Lda., Portugal) Jose M. Costa (Faculty of Engineering of the University of Porto, Portugal) Elsa W. Sequeiros (Faculty of Engineering of the University of Porto, Portugal)

Abstract:

This study investigates the comprehensive characterization of Inconel 718 powder and specimens produced by Laser Powder Bed Fusion (L-PBF). The powder exhibited spherical morphology with a D50 of 23 µm, demonstrating good flowability with a Hausner ratio of 1.10 ±0.01 and Hall flow of 21.8 ±0.5 s|50g. As-built specimens showed dendritic microstructure with Laves phase, while heat-treated samples developed wrought microstructure with d phase precipitates. Heat treatment significantly enhanced mechanical properties, increasing yield strength from 566 MPa to 1135 MPa and ultimate strength from 858 MPa to 1286 MPa, though elongation decreased from 36.8% to 19.4%. Microhardness improved from 285 HV0.2 to 492 HV0.2 in the building direction, with anisotropy increasing from 3.6% to 5.4% post-treatment. The builds showed minimal defects and high density (>8.20 g|cm³), demonstrating the effectiveness of the L-PBF process for producing high-quality Inconel 718 components.

DOI:

https://doi.org/10.59499/EP256768283

Authors:

Maxence Guillon (1), Xavier Boulnat (2), Pauline Lambert (1), Joël Lachambre (2), Thomas Elguedj (3), Christophe Desrayaud (1)

1- Mines Saint-Étienne, Université de Lyon, LGF, France

2- INSA Lyon, Université de Lyon, MATEIS, France

3- INSA Lyon, Université de Lyon, LaMCoS, France

Abstract:

Laser Powder bed Fusion is a strong process enabling the on-demand production of components with complex geometry and high added value. Despite its strengths, there are still significant challenges to fully understanding the interaction between laser and powder. The interaction between laser and material differs significantly between single tracks and multiple tracks. In a single track, the laser only interacts with the powder. In contrast, for multiple tracks, the laser interacts also with the previously laid tracks. This underscores the inadequacy of characterizing only a single track for a comprehensive understanding of the interactions between laser and powder. Moreover, previous analyses show a focal shift that cannot be neglected on the machine used. Hence, this works aims at characterizing the melt pool during the formation of a single and multiple tracks with 316L powder material. The consequence of the focal shift is observed and measured.

DOI:

https://doi.org/10.59499/EP246281572

Authors:

Mohammad Ibrahim (University of Agder, Norway), Tor Oskar Saetre (University of Agder, Norway), Ragnhild Elizabeth Aune (Norwegian University of Science and Technology, Norway)

Abstract:

In general, silicide-based materials offer efficient improvement of turbines and offshore systems due to their exceptional oxidation, corrosion, and wear resistance. The standard requirement of materials used in these systems is the ability to withstand high temperatures. Nickel silicide (NiSi) is commonly known to possess these abilities, however, its inherent brittleness makes large scale production difficult using standard metal forming techniques. Laser Metal Deposition (LMD) is an Additive Manufacturing (AM) technique similar to cladding that allows pore-free microstructure formation of the metal with refined grains, enabling excellent mechanical properties. In the present study, NiSi16 is deposited on structural steel and nickel substrates, and microstructural development is observed in both cases. The deposited beads are characterised using conventional analytical techniques, i.e., LVFESEM, EDX and XRD, and the results are discussed in the context of changes in chemical composition.

DOI:

https://doi.org/10.59499/WP225372124

Authors:

In-Seo Kim (1), Ye-Eun Lee (1), Sung-Jae Jo (1), Jong-Un Moon (1), Ji-Woon Lee (1), Dae-Hyeon Kim (1), Vasudevan Rathinam (1), Hyoung-Seop Kim (2), Soon-Jik Hong (1)

1- Division of Advanced Materials Engineering and Center for Advanced Materials and Parts of Powder (CAMP2), Kongju National University, Cheonan, Republic of Korea

2- Pohang University of Science and Technology, Pohang, Republic of Korea

Abstract:

The effect of as-received (original) and recycled powders on the microstructure and mechanical properties of the STS 316L alloy manufactured using the direct energy deposition (DED) process was explored. The original and recycled powder formed around the additively manufactured material during the DED process was collected and used as starting materials. Two rectangular STS 316L specimens with dimensions of 30x30x20 mm3 were produced using original and recycled powders. The gas-atomized STS 316L powder possesses a spherical shape, and dendrite structure and pores were found in the recycled powder. STS 316L bulk alloy exists in the single-phase FCC crystal structure, and δ-ferrite residual was observed for the recycled powder. The tensile test revealed no significant difference in the maximum tensile strength for both original and recycled powder; however; there was a notable decrease of 50% in elongation for the as-built sample manufactured with the recycled powder.

DOI:

https://doi.org/10.59499/EP246282795

Authors:

Angel Sota-Munoz (CEIT-BRTA, Spain), Nerea Burgos (CEIT-BRTA, Spain), Mihail Ipatov (UPV|EHU, Spain), Jose Manuel Martin (CEIT-BRTA, Spain), Julian Gonzalez (UPV|EHU, Spain)

Abstract:

Iron silicon gas atomized powder was coated with iron phosphate, epoxy resin and a mix of both to make soft magnetic composites (SMC). Iron phosphate composites were consolidated by cold pressing at 800 MPa or hot pressing at 825 ºC and 50 MPa. Composites made from epoxy resin or a mix of epoxy|phosphate were consolidated by cold pressing at 800 MPa. The microstructural characterization of the new cores was carried out by high resolution scanning electron microscopy. Differential scanning calorimetry showed that a degradation of the phosphate coating occurs at temperatures above ~880 ºC due to a reaction with silicon, limiting the maximum temperature for hot pressing. The best combination of properties was obtained for the hot-pressed iron phosphate composite, reaching high density (6.59 g|cm3), high electrical resistivity (~105 µO·cm), high saturation magnetization (1.75 T) and a low coercive field (~315 A|m).

DOI:

https://doi.org/10.59499/WP225371898

Authors:

Jose Costa (FEUP, Portugal) Bernardo Tavares (FEUP, Portugal) Gonçalo Cruz (FEUP, Portugal) Ines Silva (FEUP, Portugal) Jose Silva (FEUP, Portugal) Pilar Rodríguez (AIMEN, Spain) Elsa Sequeiros (FEUP, Portugal)

Abstract:

The performance of Laser Powder Bed Fusion (LPBF) is highly dependent on the quality of the metallic powder feedstock. This study characterizes a gas-atomized Ti6Al4V (Grade 5) powder, analyzing morphology, particle size distribution, flowability, true density, chemical composition, phase constitution, and thermal stability. Optical and SEM imaging revealed predominantly spherical particles with some irregular shapes and satellites. Particle size analysis showed that only 46.49% of the volume fell within the specified 5–22?µm range, contributing to poor flowability (Hausner Ratio 1.86; Carr Index 46%). True density (4.35 g|cm³) closely matched the theoretical value, indicating low internal porosity. SEM|EDS confirmed the alloy composition but detected elevated oxygen levels. X-ray diffraction revealed an a-phase structure, while thermogravimetric analysis showed thermal stability up to 400?°C, followed by gradual oxidation. The results emphasize the critical influence of powder characteristics on LPBF processability and highlight the importance of stringent powder quality control to ensure reliable outcomes.

DOI:

https://doi.org/10.59499/EP256768096

Authors:

B. Guimarães (1), C. M. Fernandes (2), D. Figueiredo (2), F. S. Silva (1), G. Miranda (3)

1- Center for MicroElectroMechanical Systems (CMEMS-UMinho), University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal

2- Palbit S.A., P.O. Box 4, 3854-908 Branca, Portugal

3- CICECO, Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal

Abstract:

During machining processes, a large amount of heat is generated, especially in the cutting zone, due to the deformation of the material and to the friction of the chip along the surface of the cutting tool, resulting in, a wear increase and consequent reduction of tool life. Surface texturing can help improve these tools tribological performance by increasing their load carrying capacity, providing a more efficient lubricant supply at the tool-chip interface and reducing the tool-chip contact area. In this context, the fabrication of cross-hatched micropatterns on WC-Co cutting tools by laser surface texturing of green compacts is proposed, aiming to improve these tools performance and life. This work is focused on evaluating the morphology of the chip obtained when turning 316L stainless steel with tools textured with different cross-hatched micropatterns, these findings being benchmarked against conventional cutting tools and correlated with the tool wear. For such purpose, morphological characterization using optical and scanning electron microscopy was used.

DOI:

https://doi.org/10.59499/EP235765436

Authors:

Christian-Gierl-Mayer (1), Herbert Danninger (1)

1- TU Wien, Austria

Abstract:

Additives in PM steels are widely used to improve machinability in turning or other machining operations. Commonly, MnS is added because it is cheap and does not have an excessive influence on the mechanical properties. However, MnS tends to form agglomerates and increases the susceptibility to corrosion in the sintered products. Potential alternatives could be sulfides of chromium or tungsten. In the present study these were compared with MnS at two different sintering temperatures. In addition to the thermal stability, both the machinability in turning and the mechanical properties were investigated. It turned out that at least Cr2S3 is a potential candidate as a cutting aid when sintering is done at belt furnace temperatures. Although WS2 seems to be effective, detailed analysis shows that this effectiveness is in fact due to the presence of MnS, which is formed during sintering by an internal getter effect.

DOI:

https://doi.org/10.59499/EP246281579