Mid Sweden University

miun.sePublications
Change search
Link to record
Permanent link

Direct link
Alternative names
Publications (10 of 85) Show all publications
Sjöström, W., Koptyug, A., Rännar, L.-E. & Botero, C. (2024). Near-infrared radiation: A promising heating method for powder bed fusion. Materials and Manufacturing Processes, 39(3), 320-328
Open this publication in new window or tab >>Near-infrared radiation: A promising heating method for powder bed fusion
2024 (English)In: Materials and Manufacturing Processes, ISSN 1042-6914, E-ISSN 1532-2475, Vol. 39, no 3, p. 320-328Article in journal (Refereed) Published
Abstract [en]

Metal additive manufacturing technologies, such as electron beam powder bed fusion (PBF-EB), rely on layer heating to overcome the so-called “smoke” phenomenon. When scaled up for industrial manufacturing, PBF-EB becomes less productive due to the lengthy preheating process. Currently, only the electron beam (EB) is used for preheating in PBF-EB, resulting in increased manufacturing times, energy consumption, and in some cases limiting the applicability of the technology. In this study, a new preheating approach is suggested that incorporates a near-infrared radiation (NIR) emitter inside an PBF-EB system. The NIR unit eliminates the need for EB heating, reducing build time and powder charging. Successful builds using 316 L and Ti6Al4V precursor powders validate the feasibility of the proposed approach. The produced samples exhibit similar properties to those obtained by the standard PBF-EB process. The introduction of NIR technology also reduced build cost and increased the service intervals of the electron gun. 

Place, publisher, year, edition, pages
Informa UK Limited, 2024
Keywords
316L, additive, beam, Electron, infrared, manufacturing, Ti6Al4V
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-48165 (URN)10.1080/10426914.2023.2195910 (DOI)000961192700001 ()2-s2.0-85152071465 (Scopus ID)
Available from: 2023-04-19 Created: 2023-04-19 Last updated: 2024-02-27Bibliographically approved
Roos, S., Barbera Flichi, F., Ortiz-Membrado, L., Botero Vega, C. A., Jiménez-Piqué, E. & Rännar, L.-E. (2023). Assessing the viability of high-frequency spot melting for super duplex stainless steel 2507 via electron beam powder bed fusion. Journal of Materials Research and Technology, 27, 5720-5728
Open this publication in new window or tab >>Assessing the viability of high-frequency spot melting for super duplex stainless steel 2507 via electron beam powder bed fusion
Show others...
2023 (English)In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 27, p. 5720-5728Article in journal (Refereed) Published
Abstract [en]

This study investigates the use of Electron Beam Powder Bed Fusion (PBF-EB) spot melting on SDSS 2507, a material known for its high tensile strength, corrosion resistance, and welding properties. Spot melting, a localized melting technique, utilize a stationary beam to create melt pools before rapidly repositioning to form new ones, offering precise control over material properties in additive manufacturing. We conducted a design of experiments with 32 samples and analysed them using SEM, XRD, EBSD, optical microscopy, nanoindentation and statistical modelling. Elevated PBF-EB processing temperatures significantly influence microstructure and phase composition. XRD analysis identified the presence of the detrimental sigma phase. EBSD analysis revealed a composition primarily consisting of austenite (63 %) and sigma phase (33.5 %), with residual ferrite (3.5 %). Statistical modelling demonstrated that a combination of spot-time, spot distance, focus offset, and layer thickness was the most reliable predictor for density while area energy proved to be the most accurate predictor for hardness, with R2adj values of 0.766 and 0.802, respectively. Our study confirms that PBF-EB is capable of processing SDSS 2507 through spot melting, resulting in high-density samples at high productivity rates. The presence of sigma phase shows a need for post build heat treatment to achieve the desired phase distribution. This research enhances the understanding of the process and also holds promise for industrial applications. 

Place, publisher, year, edition, pages
Elsevier BV, 2023
Keywords
2507, Additive manufacturing, EBSD, Electron beam powder bed fusion, Nanoindentation, Stainless steel
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:miun:diva-49961 (URN)10.1016/j.jmrt.2023.11.028 (DOI)001148284900001 ()2-s2.0-85176960460 (Scopus ID)
Available from: 2023-11-30 Created: 2023-11-30 Last updated: 2024-02-09Bibliographically approved
Roos, S., Botero, C. & Rännar, L.-E. (2023). Electron beam powder bed fusion processing of 2507 super duplex stainless steel. as-built phase composition and microstructural properties. Journal of Materials Research and Technology, 24, 6473-6483
Open this publication in new window or tab >>Electron beam powder bed fusion processing of 2507 super duplex stainless steel. as-built phase composition and microstructural properties
2023 (English)In: Journal of Materials Research and Technology, ISSN 2238-7854, Vol. 24, p. 6473-6483Article in journal (Refereed) Published
Abstract [en]

This study focuses on adapting the Electron Beam Powder Bed Fusion (E-PBF) process for the manufacturing of parts from 2507 super duplex stainless steel, combining high strength and corrosion resistance, therefore presenting an interesting choice for E-PBF implementation. Samples manufactured using four sets of process parameters were characterized by scanning electron microscopy, tensile testing, X-ray diffraction analysis, energy dispersive X-ray spectroscopy and nanoindentation. The different E-PBF process temperatures investigated had the strongest influence on the phase characteristics and the resulting microstructure. The processability of the material was good, and high productivity rates were achieved, indicating good suitability for industrial transfer.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
1.4410, 2507, Additive manufacturing, Electron beam powder bed fusion, Nanoindentation, Stainless steel
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:miun:diva-48320 (URN)10.1016/j.jmrt.2023.04.230 (DOI)001026745000001 ()2-s2.0-85156260914 (Scopus ID)
Available from: 2023-05-16 Created: 2023-05-16 Last updated: 2023-09-19Bibliographically approved
Botero, C., Koptyug, A., Sjöström, W., Jiménez-Piqué, E., Şelte, A. & Rännar, L.-E. (2023). Functionally Graded Steels Obtained via Electron Beam Powder Bed Fusion. Key Engineering Materials, 964, 79-84
Open this publication in new window or tab >>Functionally Graded Steels Obtained via Electron Beam Powder Bed Fusion
Show others...
2023 (English)In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 964, p. 79-84Article in journal (Refereed) Published
Abstract [en]

Electron-Beam Powder Bed Fusion (EB-PBF) is one of the most important metal additive manufacturing (AM) technologies. In EB-PBF, a focused electron beam is used to melt metal powders in a layer by layer approach. In this investigation two pre-alloyed steel-based powders, stainless steel 316L and V4E, a tool steel developed by Uddeholm, were used to manufacture functionally graded materials. In the proposed approach two powders are loaded into the feeding container, V4E powder on top of 316L one, preventing their mixing. Such type of feeding yields components with two distinct materials separated by a zone with gradual transition from 316L to V4E. Microstructure and local mechanical properties were evaluated in the manufactured samples. Optical Microscopy, Scanning Electron Microscopy and EDX on the polished cross-sections show a gradual microstructural and compositional transition from characteristic 316L at the bottom of the specimens to the tool steel towards the top. Nanoindentation experiments confirmed a consequent gradient in hardness and elastic modulus, which gradually increase towards the top surface of the samples. The achieved results provide great possibilities to tailor the composition, microstructure, mechanical properties, and wear resistance by combining different powders in the powder bed AM technology. Potential applications include the tooling industry, where hard and wear-resistant materials are demanded on the surface with tougher and more ductile materials in the core of the tool.

Place, publisher, year, edition, pages
Trans Tech Publications, Ltd., 2023
Keywords
Electron Beam Melting, Functional Graded Materials (FGMs), Nanoindentation, Steel
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:miun:diva-50147 (URN)10.4028/p-xaC6qO (DOI)
Available from: 2023-12-20 Created: 2023-12-20 Last updated: 2023-12-20Bibliographically approved
Botero, C., Sjöström, W., Jimenez-Piqué, E., Şelte, A. & Rännar, L.-E. (2023). PBF-EB For Manufacturing Of 3D Metal-Metal Multi Material Assemblies. In: Euro Powder Metallurgy 2023 Congress and Exhibition, PM 2023: . Paper presented at Euro Powder Metallurgy 2023 Congress and Exhibition, PM 2023. European Powder Metallurgy Association
Open this publication in new window or tab >>PBF-EB For Manufacturing Of 3D Metal-Metal Multi Material Assemblies
Show others...
2023 (English)In: Euro Powder Metallurgy 2023 Congress and Exhibition, PM 2023, European Powder Metallurgy Association , 2023Conference paper, Published paper (Refereed)
Abstract [en]

Most Powder Bed Fusion (PBF) methods for the Additive Manufacturing (AM) of metals are based on the melting of powder of one specific metallic material; either of pure-elemental or pre-alloyed composition. Although the potential to build components from different materials in AM has recently gained a lot of attention, it is still not feasible in the current metal PBF systems. In the specific case of Electron beam- based PBF (PBF-EB), it is possible to precisely control the beam parameters in each site of the build area, which opens great possibilities for adaptive processes that allows melting powders of different nature in the same build. In this investigation, different steel-based and Ti6Al4V alloy powders are used to create metal-metal assemblies. By steering the fetching of two powders loaded in different hoppers it was possible to build different metal-metal assemblies. The microstructure and mechanical properties of the final materials were evaluated. 

Place, publisher, year, edition, pages
European Powder Metallurgy Association, 2023
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-50225 (URN)10.59499/EP235735468 (DOI)2-s2.0-85180376917 (Scopus ID)
Conference
Euro Powder Metallurgy 2023 Congress and Exhibition, PM 2023
Available from: 2024-01-08 Created: 2024-01-08 Last updated: 2024-02-27Bibliographically approved
Sjöström, W., Botero, C., Jimenez-Pique, E., Selte, A. & Rännar, L.-E. (2023). Steel-based multi-material configurations by PBF-EB. In: Dr. María Teresa Pérez-Prado (Ed.), : . Paper presented at Alloys for Additive Manufacturing Symposium, Madrid, Spain, September 27th-29th, 2023. Madrid
Open this publication in new window or tab >>Steel-based multi-material configurations by PBF-EB
Show others...
2023 (English)In: / [ed] Dr. María Teresa Pérez-Prado, Madrid, 2023Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Most Powder Bed Fusion (PBF) methods for the Additive Manufacturing (AM) of metals are based on manufacturing components by the melting of powder feedstock of one kind; either of pure-elemental or pre-alloyed compositions. Although the AM of multi-materials has recently gained a lot of attention, it is still not commercially available for metal PBF. In Electron-beam based PBF (EB-PBF) it is possible to control precisely the beam parameters such as speed, spot size and current in each site of the build area. By doing this for each manufactured layer, the melting and solidification process can be steered throughout the build. This opens great possibilities for adaptive processes that allows melting of feedstock powders of different nature in the same build. In this investigation, different steel-based powders are used to create metal-metal multimaterials, including stainless-, hot-work and cold-work tool steels. In the proposed approach, each of the two hoppers is loaded with different metal feedstock so that the fetching can be steered to dispense each specific powder into the bed layer-by-layer. By doing so, the process was steered to obtain multimaterials with lamellar, sandwich-like, and compositionally graded configurations. The microstructure and micromechanical properties of the obtained specimens were characterized by microscopic techniques and nanoindentation.

Place, publisher, year, edition, pages
Madrid: , 2023
Keywords
Multi-materials, 316L, V4E, Electron, Powder, Bed, Fusion
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:miun:diva-49514 (URN)
Conference
Alloys for Additive Manufacturing Symposium, Madrid, Spain, September 27th-29th, 2023
Available from: 2023-10-11 Created: 2023-10-11 Last updated: 2023-10-16Bibliographically approved
Hosseini, S. B., Mallipeddi, D., Holmberg, J., Rännar, L.-E., Koptyug, A., Sjöström, W., . . . Klement, U. (2022). Comparison of machining performance of stainless steel 316L produced by selective laser melting and electron beam melting. In: Procedia CIRP: . Paper presented at 10th CIRP Global Web Conference on Material Aspects of Manufacturing Processes, 25 October 2022 through 27 October 2022 (pp. 72-77). Elsevier
Open this publication in new window or tab >>Comparison of machining performance of stainless steel 316L produced by selective laser melting and electron beam melting
Show others...
2022 (English)In: Procedia CIRP, Elsevier, 2022, p. 72-77Conference paper, Published paper (Refereed)
Abstract [en]

Powder bed fusion processes based additively manufactured SS 316L components fall short of surface integrity requirements needed for optimal functional performance. Hence, machining is required to achieve dimensional accuracy and to enhance surface integrity characteristics. This research is focused on comparing the material removal performance of 316L produced by PBF-LB (laser) and PBF-EB (electron beam) in terms of tool wear and surface integrity. The results showed comparable surface topography and residual stress profiles. While the hardness profiles revealed work hardening at the surface where PBF-LB specimens being more susceptible to work hardening. The investigation also revealed differences in the progress of the tool wear when machining specimens produced with either PBF-LB or PBF-EB. 

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Additive manufacturing, electron beam melting, machining, selective laser melting, surface integrity
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-46791 (URN)10.1016/j.procir.2022.10.052 (DOI)2-s2.0-85145230165 (Scopus ID)
Conference
10th CIRP Global Web Conference on Material Aspects of Manufacturing Processes, 25 October 2022 through 27 October 2022
Available from: 2023-01-10 Created: 2023-01-10 Last updated: 2023-01-10Bibliographically approved
Quiceno, E., Botero Vega, C. A., Rännar, L.-E., Castano, J., Gomez, M., Baena, L., . . . Tamayo, J. (2022). Customized Ti6Al4V implants by EBM: design, manufacturing and surface treatments. In: Proceedings: . Paper presented at IC-EXPOI 2022: International Congress - EXPO Ingeniería 2022, Engineering for Transformation, Medellin, Colombia, Oct 27-29, 2022 (pp. 381-388).
Open this publication in new window or tab >>Customized Ti6Al4V implants by EBM: design, manufacturing and surface treatments
Show others...
2022 (English)In: Proceedings, 2022, p. 381-388Conference paper, Published paper (Refereed)
Abstract [en]

Subtractive manufacturing methods such as machining have been conventionally used to produce standard metallic implants for bone replacement in materials such as Co-Cr and Ti-based alloys. The production of a customized implant with complex geometries using conventional machining techniques such as CNC requires specification equipment (5 or 6 axes), where the manufacturing process is difficult, limiting the mass production of customized products. New advanced metal additive manufacturing (AM) methods allow patient-specific implants obtaining, in which the Engineering for Transformation implant geometry can be designed to fit to a specific patient from the information of a CT scan. Besides this flexibility in the design, AM offers a cleaner production with less generation of scrap, low energy consumption and lower CO2 release. Electron Beam Melting (EBM) is one of the most used AM methods in the implant industry. In EBM, an electron beam is used to melt metal powder layer by layer in a vacuum protective environment, following a digital 3D model. Titanium alloys, specifically Ti6Al4V, have been the most widely used biomaterial in biomedical applications of orthopedic implants. In general, implants for biomedical applications require postmanufacturing surface modification to improve their performance, biocompatibility and fixation with the surrounding tissues in the area where they are implanted. Formation of anodic layers is one of the surface modifications that have become essential due to the high demands of implant applications and in order to enhance chemical and mechanical properties of the surface specimen. The most common anodizing developments were performed on Ti6Al4V alloy surfaces manufactured by conventional technologies such as forging and conventional machining. The project explores the feasibility of EBM of metal implants prototypes manufacturing for the Colombian healthcare market. 3D implant models were obtained, and then manufactured using EBM in Ti6Al4V alloy. A PEO process to surface modification with the aim to improve the biocompatibility of the manufactured implants by EMB process were demonstrated.

Keywords
Additive manufacturing (AM); Electron Beam Melting (EBM); Ti6Al4V implants, customized; PEO process.
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:miun:diva-47627 (URN)978-628-95287-1-8 (ISBN)
Conference
IC-EXPOI 2022: International Congress - EXPO Ingeniería 2022, Engineering for Transformation, Medellin, Colombia, Oct 27-29, 2022
Available from: 2023-02-22 Created: 2023-02-22 Last updated: 2023-02-22Bibliographically approved
Molavitabrizi, D., Bengtsson, R., Botero, C., Rännar, L.-E. & Mahmoud Mousavi, S. (2022). Damage-induced failure analysis of additively manufactured lattice materials under uniaxial and multiaxial tension. International Journal of Solids and Structures, 252, Article ID 111783.
Open this publication in new window or tab >>Damage-induced failure analysis of additively manufactured lattice materials under uniaxial and multiaxial tension
Show others...
2022 (English)In: International Journal of Solids and Structures, ISSN 0020-7683, E-ISSN 1879-2146, Vol. 252, article id 111783Article in journal (Refereed) Published
Abstract [en]

Mechanical behavior of additively manufactured lattice materials has been mainly investigated under uniaxial compression, while their performance under uniaxial and multiaxial tension are yet to be understood. To address this gap, a generic elastoplastic homogenization scheme with continuum damage model is developed, and three different lattice materials, namely cubic, modified face-center cubic and body-center cubic, are analyzed under uniaxial, biaxial and triaxial tension. The influence of micro-architecture on the material's failure behavior as well as its macroscopic mechanical performance is thoroughly discussed. For validation, a set of uniaxial tensile experiments are conducted on functionally graded cubic lattice samples that are additively manufactured using Electron Beam Melting (EBM) process. Digital image correlation technique is employed to obtain the macroscopic stress–strain curves, and manufacturing imperfections are inspected using light omitting microscopy. It turns out that the behavior of as-built samples could substantially differ from numerical predictions. Thus, a defect-informed numerical model is employed to accommodate the effect of imperfections. The outcome is in a very good agreement with experimental data, indicating that with proper input data, the developed scheme can accurately predict the mechanical and failure behavior of a given lattice material. 

Keywords
Continuum damage, Elastoplastic homogenization, Electron beam melting, Failure mechanics, Lattice materials, Manufacturing defects, Multiaxial tension
National Category
Mechanical Engineering
Identifiers
urn:nbn:se:miun:diva-45730 (URN)10.1016/j.ijsolstr.2022.111783 (DOI)000833524100001 ()2-s2.0-85132220129 (Scopus ID)
Available from: 2022-08-01 Created: 2022-08-01 Last updated: 2022-08-18Bibliographically approved
Ramsberger, M., Botero Vega, C. A., Rännar, L.-E. & Selte, A. (2022). Electron Beam-based Additive Manufacturing of highly alloyed cold work tool steels and tungsten carbide Metal Matrix Composites: from research to industrialization. In: Proceedings: . Paper presented at 12th Tooling Conference & Exhibition, Tooling 2022, 25-27 April 2022, Örebro, Sweden.
Open this publication in new window or tab >>Electron Beam-based Additive Manufacturing of highly alloyed cold work tool steels and tungsten carbide Metal Matrix Composites: from research to industrialization
2022 (English)In: Proceedings, 2022Conference paper (Refereed)
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-47629 (URN)
Conference
12th Tooling Conference & Exhibition, Tooling 2022, 25-27 April 2022, Örebro, Sweden
Available from: 2023-02-22 Created: 2023-02-22 Last updated: 2023-02-22Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-5954-5898

Search in DiVA

Show all publications