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Bäckström, Mikael
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Publications (10 of 69) Show all publications
Koptioug, A., Popov, V. V. ., Botero Vega, C. A., Jiménez-Piqué, E., Katz-Demyanetz, A., Rännar, L.-E. & Bäckström, M. (2020). Compositionally-tailored steel-based materials manufactured by electron beam melting using blended pre-alloyed powders. Materials Science & Engineering: A, 771, Article ID 138587.
Open this publication in new window or tab >>Compositionally-tailored steel-based materials manufactured by electron beam melting using blended pre-alloyed powders
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2020 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 771, article id 138587Article in journal (Refereed) Published
Abstract [en]

The paper presents the prospects of additive manufacturing (AM) in metal, using the powder bed fusion (PBF) method Electron Beam Melting (EBM) in fabrication specific steel-based alloys for different applications. The proposed approach includes manufacturing of metals from blended pre-alloyed powders for achieving in situ alloying and the material microstructure tailoring by controlling electron beam energy deposition rate EBM tests were conducted with the blends of 316L stainless steel and Colferoloys 103 and 139, corrosion- and abrasion-resistant iron based materials commonly used for plasma spray coating. Thorough microstructure analysis of the manufactured sample was carried out using electron microscopy and measurements of microhardness and elastic modulus was carried out using nanoindentation. It is concluded that implementation of blended powder pathway in PBF AM allows to widen the scope of available materials through diminishing the dependence on the availability of pre-alloyed powders. Together with beam energy steering this pathway also allows for an effective sample microstructure control at different dimensional scales, resulting in components with unique properties. Therefore, the implementation of ‘blended powder pathway’ in PBF AM provides a possibility of manufacturing components with the composite-like and homogeneous zones allowing for the microstructure control and effectively adding a “4th dimension” to “3D printing". 

Keywords
Additive manufacturing, Blended powder, EBM, Electron beam melting, Graded material, In situ alloying
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-37689 (URN)10.1016/j.msea.2019.138587 (DOI)000503324700020 ()2-s2.0-85074019741 (Scopus ID)
Available from: 2019-11-15 Created: 2019-11-15 Last updated: 2020-01-16Bibliographically approved
Botero, C., Bäckström, M., Rännar, L.-E., Roos, S., Koptyug, A., Åsvik, K., . . . Ramsperger, M. (2019). Additive Manufacturing of a cold work steel using Electron Beam Melting. In: Proceedings of Conference:  Tooling 2019: . Paper presented at Tooling 2019, Aachen, May 2019. , May
Open this publication in new window or tab >>Additive Manufacturing of a cold work steel using Electron Beam Melting
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2019 (English)In: Proceedings of Conference:  Tooling 2019, 2019, Vol. MayConference paper, Oral presentation with published abstract (Refereed)
Keywords
Additive Manufacturing, steel, Electron Beam Melting
National Category
Other Engineering and Technologies not elsewhere specified Metallurgy and Metallic Materials Other Mechanical Engineering
Identifiers
urn:nbn:se:miun:diva-37955 (URN)
Conference
Tooling 2019, Aachen, May 2019
Available from: 2019-12-11 Created: 2019-12-11 Last updated: 2019-12-12Bibliographically approved
Botero Vega, C. A., Ramsperger, M., Selte, A., Åsvik, K., Koptioug, A., Skoglund, P., . . . Bäckström, M. (2019). Additive Manufacturing of a Cold-Work Tool Steel using Electron Beam Melting. Steel Research International, 1-6, Article ID 1900448.
Open this publication in new window or tab >>Additive Manufacturing of a Cold-Work Tool Steel using Electron Beam Melting
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2019 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, p. 1-6, article id 1900448Article in journal (Refereed) Published
Abstract [en]

Metal additive manufacturing (AM) is on its way to industrialization. One of the most promising techniques within this field, electron beam melting (EBM), is nowadays used mostly for the fabrication of high‐performance Ti‐based alloy components for the aerospace and medical industry. Among the industrial applications envisioned for the future of EBM, the fabrication of high carbon steels for the tooling industry is of great interest. In this context, the process windows for dense and crack‐free specimens for a highly alloyed (Cr–Mo–V) cold‐work steel powder are presented in this article. High‐solidification rates during EBM processing lead to very fine and homogeneous microstructures. The influence of process parameters on the resulting microstructure and the chemical composition is investigated. In addition, preliminary results show very promising mechanical properties regarding the as‐built and heat‐treated microstructure of the obtained material.

National Category
Other Materials Engineering
Identifiers
urn:nbn:se:miun:diva-38162 (URN)10.1002/srin.201900448 (DOI)2-s2.0-85075934124 (Scopus ID)
Funder
Interreg Sweden-Norway, 20201562
Available from: 2019-12-20 Created: 2019-12-20 Last updated: 2020-02-21Bibliographically approved
Petrone, N., Candiotto, G., Marzella, E., Uriati, F., Carraro, G., Bäckström, M. & Koptyug, A. (2019). Feasibility of using a novel instrumented human head surrogate to measure helmet, head and brain kinematics and intracranial pressure during multidirectional impact tests. Journal of Science and Medicine in Sport, 22(S1), S78-S84
Open this publication in new window or tab >>Feasibility of using a novel instrumented human head surrogate to measure helmet, head and brain kinematics and intracranial pressure during multidirectional impact tests
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2019 (English)In: Journal of Science and Medicine in Sport, ISSN 1440-2440, E-ISSN 1878-1861, Vol. 22, no S1, p. S78-S84Article in journal (Refereed) Published
Abstract [en]

Objectives: Aim of the work is to present the feasibility of using an Instrumented Human Head Surrogate (IHHS-1) during multidirectional impacts while wearing a modern ski helmet. The IHHS-1 is intended to provide reliable and repeatable data for the experimental validation of FE models and for the experimental evaluation of modern helmets designed to enhance the degree of protection against multidirectional impacts. Design: The new IHHS-1 includes 9 triaxial MEMS accelerometers embedded in a silicone rubber brain, independently molded and presenting lobes separation and cerebellum, placed into an ABS skull filled with surrogate cerebrospinal fluid. A triaxial MEMS gyroscope is placed at the brain center of mass. Intracranial pressure can be detected by eight pressure sensors applied to the skull internal surface along a transversal plane located at the brain center of mass and two at the apex. Additional MEMS sensors positioned over the skull and the helmet allow comparison between outer and inner structure kinematics and surrogate CSF pressure behavior. Methods: The IHHS-1 was mounted through a Hybrid III neck on a force platform and impacted with a striker connected to a pendulum tower, with the impact energies reaching 24J. Impact locations were aligned with the brain center of mass and located in the back (sagittal axis), right (90° from sagittal axis), back/right (45°), and front right (135°) locations. Following dynamic data were collected: values of the linear accelerations and angular velocities of the brain, skull and helmet; intracranial pressures inside the skull. Results: Despite the relatively low intensity of impacts (HIC at skull max value 46), the skull rotational actions reached BrIC values of 0.33 and angular accelerations of 5216 rad/s2, whereas brain angular acceleration resulted between 1,44 and 2,1 times lower with similar values of BrIC. Conclusions: The IHHS-1 is a physical head surrogate that can produce repeatable data for the interpretation of inner structures behavior during multidirectional impacts with or without helmets of different characteristics. 

Keywords
Accelerometers, Angular velocity, Helmet evaluation, Human head, Intracranial pressure, Surrogate
National Category
Materials Engineering
Identifiers
urn:nbn:se:miun:diva-36704 (URN)10.1016/j.jsams.2019.05.015 (DOI)000493587000016 ()31272916 (PubMedID)2-s2.0-85068078314 (Scopus ID)
Available from: 2019-07-10 Created: 2019-07-10 Last updated: 2020-02-20Bibliographically approved
Koptyug, A., Botero, C., Sjöström, W., Jimenez-Pique, E., Şelte, A., Asvik, K., . . . Bäckström, M. (2019). Steel-based functionally gradient materials obtained via Electron Beam Melting. In: Proc. Alloys for Additive Manufacturing Symposium AAMS2019: . Paper presented at Alloys for Additive Manufacturing Symposium, AAMS2019, Göteborg, 18-20 September, 2019.
Open this publication in new window or tab >>Steel-based functionally gradient materials obtained via Electron Beam Melting
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2019 (English)In: Proc. Alloys for Additive Manufacturing Symposium AAMS2019, 2019Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Recent developments in metal Additive Manufacturing (AM) technologies have introduced great capabilities unparalleled by conventional manufacturing, not only in achieving freeform geometries, but also in opening new possibilities to tailor the microstructure/properties of materials by controlling process parameters. Electron Beam Melting (EBM) is one of the most important members of the Powder Bed Fusion(PBF) family; it uses a focused electron beam to melt metal powder in a layer by layer approach. One of the main challenges that EBM faces nowadays is the lack of commercially available materials (most of them are Ti-based or Ni-based alloys). Therefore, there is a strong interest to further develop the process for new materials, including steel-based ones. In this investigation two steel-based powders; stainless steel 316L and a tool steel developed by Uddeholm, were used to manufacture functionally graded materials. A special hardware setup using a single powder dispenser was installed in the EBM system, where powders were placed separately to manufacture 10x10x10 mm cubes. SEM images of the specimens’ polished cross sections show a gradual microstructural transition from characteristic 316L one on 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 top surface. These results show great possibilities to tailor microstructure and mechanical properties by combining different powders in the EBM technology. Potential applications include the tooling industry, where hard and wear-resistant materials are demanded on the surface whether tougher and more ductile behavior is desirable on the core of the tool.

Keywords
Additive Manufacturing, new materials, Electron Beam Melting
National Category
Other Civil Engineering Metallurgy and Metallic Materials Composite Science and Engineering
Identifiers
urn:nbn:se:miun:diva-37956 (URN)
Conference
Alloys for Additive Manufacturing Symposium, AAMS2019, Göteborg, 18-20 September, 2019
Available from: 2019-12-11 Created: 2019-12-11 Last updated: 2019-12-12Bibliographically approved
Petrone, N., Carraro, G., Dal Castello, S., Broggio, L., Koptioug, A. & Bäckström, M. (2018). A Novel Instrumented Human Head Surrogate For The Impact Evaluation Of Helmets. In: Dr Hugo Espinosa, David R. Rowlands, Jonathan Shepherd, Professor David Thiel (Ed.), Proceedings, Volume 2, ISEA 2018: . Paper presented at 12th Conference on the Engineering of Sport, Brisbane, Australia, 26 to 29 March 2018 (pp. 269). , 2, Article ID 6.
Open this publication in new window or tab >>A Novel Instrumented Human Head Surrogate For The Impact Evaluation Of Helmets
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2018 (English)In: Proceedings, Volume 2, ISEA 2018 / [ed] Dr Hugo Espinosa, David R. Rowlands, Jonathan Shepherd, Professor David Thiel, 2018, Vol. 2, p. 269-, article id 6Conference paper, Published paper (Refereed)
Abstract [en]

A novel Human Head Surrogate was obtained from available MRI scans of a 50th percentile male human head. Addictive manufacturing was used to produce the skull, the brain and the skin. All original MRI geometries were partially smoothed and adjusted to provide the best biofidelity compatible with printing and molding technology. The skull was 3D-printed in ABS and ten pressure sensors were placed into it. The brain surrogate was cast from silicon rubber in the 3d-printed plastic molds. Nine tri-axial accelerometers (placed at the tops of the lobes, at the sides of the lobes, in the cerebellum and in the center of mass) and a three-axis gyroscope (at the center of mass) were inserted into the silicon brain during casting. The cranium, after assembly with brain, was filled with silicon oil mimicking the cerebral fluid. Silicon rubber was cast in additional 3d-printed molds to form the skin surrounding the cranium. The skull base was adapted to be compatible with the Hybrid-III neck and allow the exit of brain sensors cabling. Preliminary experiments were carried out proving the functionality of the surrogate. Results showed how multiple accelerometers and pressure sensors allowed a better comprehension of the head complex motion during impacts.

Keywords
human head, surrogate, additive manufacturing, accelerometers, impact tests
National Category
Medical Laboratory and Measurements Technologies Other Materials Engineering Other Mechanical Engineering Interaction Technologies
Identifiers
urn:nbn:se:miun:diva-32502 (URN)10.3390/proceedings2060269 (DOI)
Conference
12th Conference on the Engineering of Sport, Brisbane, Australia, 26 to 29 March 2018
Projects
STII
Funder
VINNOVA
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-04-25Bibliographically approved
Koptioug, A., Bäckström, M., Botero Vega, C. A., Popov, V. & Chudinova, E. (2018). Developing new materials for Electron Beam Melting: experiences and challenges. In: : . Paper presented at THERMEC'2018 International Conference on Processing and Manufacturing of Advanced Materials Processing, Fabrication, Properties, Applications, Paris, France July 8-13, 2018 (pp. 2190-2195). , 941
Open this publication in new window or tab >>Developing new materials for Electron Beam Melting: experiences and challenges
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2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Lack of industrially available materials for additive manufacturing (AM) of metallic materials along with the promises of materials with improved or unique properties provides a strong drive for developing new process/material combinations. As powder bed technologies for metallic materials are relatively new to the market, and to some extent are only maturing, developers of new process/material combinations have certain challenges to overcome. Firstly, basic knowledge on the behavior of materials (even those well established for other applications) under extreme conditions of melting/solidification with beam-based AM methods is far from being adequate. Secondly, manufacturing of the equipment is up to date driven by industrial application, thus optimization of the AM machines for small test batches of powders is still belongs to research and development projects. Also, majority of the powder manufacturers are primarily driven by the market development, and even they are well aware of the demands imposed by the powder bed AM machines, availability of small test batches of adequate powders may be problematic or at least quite costly for the R&D oriented users. Present paper describes the experiences in developing new materials for EBM A2 machine by Arcam EBM, modified for operating with powder batches of 100-200 ml and less. In particular it discusses achievements and challenges of working with powders from different materials with specifications far beyond the range suggested by machine manufacturer. Also it discusses the possibility of using blended rather than pre-alloyed powders for achieving both composite-like and alloyed materials in the same part by steering electron beam energy deposition strategy.

Keywords
Additive Manufacturing, Electron Beam Melting, material development, blended powders, in situ alloying, composite materials
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:miun:diva-35136 (URN)10.4028/www.scientific.net/MSF.941.2190 (DOI)000468152500361 ()2-s2.0-85061041310 (Scopus ID)
Conference
THERMEC'2018 International Conference on Processing and Manufacturing of Advanced Materials Processing, Fabrication, Properties, Applications, Paris, France July 8-13, 2018
Note

Paper accepted, in print

Available from: 2018-12-10 Created: 2018-12-10 Last updated: 2020-02-20Bibliographically approved
Botero Vega, C. A., Jiménez-Piqué, E., Roos, S., Skoglund, P., Koptioug, A., Rännar, L.-E. & Bäckström, M. (2018). Nanoindentation: a suitable tool in metal Additive Manufacturing. In: : . Paper presented at Materials Science & Technology, MS&T 2018, October 14-18, Columbus, USA.
Open this publication in new window or tab >>Nanoindentation: a suitable tool in metal Additive Manufacturing
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2018 (English)Conference paper, Oral presentation only (Refereed)
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:miun:diva-35342 (URN)
Conference
Materials Science & Technology, MS&T 2018, October 14-18, Columbus, USA
Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2019-01-09Bibliographically approved
Skoglund, P., Botero Vega, C. A., Koptioug, A., Rännar, L.-E. & Bäckström, M. (2018). Possibility of the “cold start” of the build in Electron Beam Melting. In: : . Paper presented at Materials Science & Technology, MS&T 2018, October 14-18, Columbus, USA.
Open this publication in new window or tab >>Possibility of the “cold start” of the build in Electron Beam Melting
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2018 (English)Conference paper, Oral presentation only (Refereed)
National Category
Other Mechanical Engineering
Identifiers
urn:nbn:se:miun:diva-35345 (URN)
Conference
Materials Science & Technology, MS&T 2018, October 14-18, Columbus, USA
Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2019-01-09Bibliographically approved
Petrone, N., Giacomin, M., Koptioug, A. & Bäckström, M. (2018). Racing Wheels’ Effect on Drag/Side Forces Acting on a Cyclist at Sportstech-Miun Wind Tunnel. In: Dr Hugo Espinosa, David R. Rowlands, Jonathan Shepherd, Professor David Thiel (Ed.), Proceedings, Volume 2, ISEA 2018: . Paper presented at 12th Conference on the Engineering of Sport, Brisbane, Australia, 26-28 March 2018 (pp. 210). , 2, Article ID 6.
Open this publication in new window or tab >>Racing Wheels’ Effect on Drag/Side Forces Acting on a Cyclist at Sportstech-Miun Wind Tunnel
2018 (English)In: Proceedings, Volume 2, ISEA 2018 / [ed] Dr Hugo Espinosa, David R. Rowlands, Jonathan Shepherd, Professor David Thiel, 2018, Vol. 2, p. 210-, article id 6Conference paper, Published paper (Refereed)
Abstract [en]

Abstract: the wind tunnel at the SportsTech Research Centre at Mid Sweden University (MIUN, Östersund) was opened in 2015 for sports technology research. It is dedicated primarily to analysis of equipment performance and garment development and especially suitable for roller skiing, running and cycling. The aim of this work was to develop a full-scale study to investigate the aerodynamic behaviour of a cyclist facing front and cross wind at different yaw angles (from 0° to 30°) and speeds. To reach this goal, a rotating structure supported by a force platform was constructed. It includes a set of rollers on which fully unrestrained cycling is possible. The method was applied to the comparison of three wheelsets (differing in material, height and shape of the rim, number and shape of spokes) in terms of drag and side aerodynamic forces during a cyclist’s ride at 30 km/h, while keeping all the other factors constant. Resulting curves allowed estimating differences of 4% and 9% when applied to a recent time trial competition.

Keywords
aerodynamics, cycling, wheels, wind tunnel, drag, side, full-scale
National Category
Fluid Mechanics and Acoustics Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
urn:nbn:se:miun:diva-32501 (URN)10.3390/proceedings2060210 (DOI)
Conference
12th Conference on the Engineering of Sport, Brisbane, Australia, 26-28 March 2018
Projects
STII
Funder
VINNOVA
Available from: 2017-12-19 Created: 2017-12-19 Last updated: 2018-04-25Bibliographically approved
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