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Neikter, M., Bhaskar, P., Singh, S., Kadoi, K., Lyphout, C., Svahn, F. & Pederson, R. (2023). Tensile properties of laser powder bed fusion built JBK-75 austenitic stainless steel. Materials Science & Engineering: A, 874, Article ID 144911.
Open this publication in new window or tab >>Tensile properties of laser powder bed fusion built JBK-75 austenitic stainless steel
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2023 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 874, article id 144911Article in journal (Refereed) Published
Abstract [en]

Laser powder bed fusion (PBF-LB) is an additive manufacturing (AM) process that has several advantages to conventional manufacturing, such as near net-shaping capabilities and reduced material wastage. To be able to manufacture a novel material, however, one needs to first optimize the process parameters, to decrease porosity content as low as possible. Therefore, in this work the process parameters of PBF-LB built JBK-75 austenitic stainless steel, and its influence on porosity, microstructure, and hardness have been investigated. The least amount of porosity was found by using 132 W laser power, 750 mm/s scan speed, layer thickness 30 μm, and 0.12 mm hatch distance. These process parameters were then used to manufacture material for tensile testing, to investigate the tensile properties of PBF-LB built JBK-75 and potential anisotropic behavior. Hot isostatic pressing (HIP) was also performed in two sets of samples, to investigate the effect of pore closure on the tensile properties. The ultimate tensile strength (UTS) for the un-HIPed specimens was 1180 (horizontally built) and 1110 (vertically built) MPa. For the HIPed specimens, it was 1160 (horizontally built) and 1100 (vertically built) MPa. The anisotropic presence was explained by the presence of texture, with a multiple of random distribution (MRD) up to 4.34 for the {001} planes, and defects. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Austenitic stainless steel, Design of experiment (DOE), JBK-75, Laser powder bed fusion (PBF-LB), Process parameters, Tensile properties, Anisotropy, Hot isostatic pressing, Porosity, Tensile strength, Tensile testing, Textures, Additive manufacturing process, Conventional manufacturing, Design of experiment, Laser powders, Material wastage, Net-shaping, Powder bed, Design of experiments
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:ri:diva-64659 (URN)10.1016/j.msea.2023.144911 (DOI)2-s2.0-85153940822 (Scopus ID)
Note

 Funding details: 20201639; Funding details: Japan Society for the Promotion of Science, KAKEN; Funding details: European Regional Development Fund, ERDF; Funding details: Tillväxtverket; Funding text 1: The authors would like to thank Marco Ravanal and James Shipley at Quintus Technologies for performing the HIP treatments. Västra Götalandsregionen through Tillväxtverket (European Regional Development Fund) and GKN Aerospace Sweden AB funded this research project through the Spacelab project (grant number 20201639). The authors would also like to thank the Japan society for the promotion of science (JSPS) summer program for funding. Sukhdeep Singh would like to acknowledge JSPS International Research Fellowship for its support.  Funding text 2: Västra Götalandsregionen through Tillväxtverket ( European Regional Development Fund ) and GKN Aerospace Sweden AB funded this research project through the Spacelab project (grant number 20201639 ). The authors would also like to thank the Japan society for the promotion of science (JSPS ) summer program for funding. Sukhdeep Singh would like to acknowledge JSPS International Research Fellowship for its support. 

Available from: 2023-05-15 Created: 2023-05-15 Last updated: 2024-04-02Bibliographically approved
Bolelli, G., Lyphout, C., Berger, L.-M. -., Testa, V., Myalska-Głowacka, H., Puddu, P., . . . Lusvarghi, L. (2023). Wear resistance of HVOF- and HVAF-sprayed (Ti,Mo)(C,N)–Ni coatings from an agglomerated and sintered powder. Wear, 512-513, Article ID 204550.
Open this publication in new window or tab >>Wear resistance of HVOF- and HVAF-sprayed (Ti,Mo)(C,N)–Ni coatings from an agglomerated and sintered powder
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2023 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 512-513, article id 204550Article in journal (Refereed) Published
Abstract [en]

(Ti,Mo)(C,N)-25 wt% Ni coatings obtained by spraying an agglomerated and sintered feedstock powder using different high velocity air-fuel (HVAF) and high velocity oxygen-fuel (HVOF) deposition processes are comparatively analysed for their sliding, abrasion and impact resistance. All HVOF-sprayed coatings are particularly dense, with ≈800 HV hardness (tested at 100 gf, 300 gf and 500 gf). In-flight oxidation resulted in some embrittlement, as revealed by scratch tests. In ball-on-disk sliding against an Al2O3 counterpart, they maintained a mild wear regime (wear rates ≤10−6 mm3/(N⋅m)) from room temperature up to 600 °C, with better performance in comparison to Cr3C2–NiCr reference coatings. At room temperature, the Ti(C,N) hard phase limited the abrasive cutting by counterbody asperities. At 400 °C and 600 °C, the coatings developed a thin, protective oxide tribofilm. They also exhibited no interface delamination in cyclic impact tests. However, they suffered higher wear (≈3–5 × 10−3 mm3/(N⋅m)) in high-stress particle abrasion testing, particularly when compared to HVAF-sprayed Cr3C2–NiCr. Gaining improved control over in-flight oxidation of (Ti,Mo)(C,N)–Ni during spraying is probably the key to overcome this limitation. The HVAF-sprayed (Ti,Mo)(C,N)–Ni coating exhibited severe interlamellar decohesion under all test conditions, as the limited melting degree of the feedstock did not compensate for the intrinsic microstructural inhomogeneity of the powder particles. 

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Abrasion, Hardmetals, High velocity air-fuel (HVAF), High velocity oxygen-fuel (HVOF), Sliding wear, Titanium carbonitride, Agglomeration, Air, Alumina, Aluminum oxide, Erosion, Feedstocks, HVOF thermal spraying, Oxygen, Sintering, Sprayed coatings, Titanium compounds, Velocity, Velocity control, Wear resistance, Agglomerated powders, Hard metals, High velocity air fuels, High velocity air-fuel, High velocity oxygen fuels, High velocity oxygen-fuel, In-flight oxidation, Ni coating, Titanium carbonitrides
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:ri:diva-61353 (URN)10.1016/j.wear.2022.204550 (DOI)2-s2.0-85142246006 (Scopus ID)
Note

Funding details: JP5000; Funding text 1: The authors would like to thank Dr. Kazuto Sato, Thermal Spray Materials Dept. Fujimi Incorporated, Japan, for providing feedstock materials and the JP5000 – HVOF coatings. The authors are especially grateful to Dr. Alberto Colella, Enrico Forlin and Simone Maset (MBN Nanomaterialia S.p.A. Vascon di Carbonera – TV – Italy) for performing the elemental analyses of carbon, nitrogen and oxygen contents in the coatings.

Available from: 2022-12-09 Created: 2022-12-09 Last updated: 2024-04-02Bibliographically approved
Čapek, J., Polatidis, E., Casati, N., Pederson, R., Lyphout, C. & Strobl, M. (2022). Influence of laser powder bed fusion scanning pattern on residual stress and microstructure of alloy 718. Materials & design, 221, Article ID 110983.
Open this publication in new window or tab >>Influence of laser powder bed fusion scanning pattern on residual stress and microstructure of alloy 718
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2022 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 221, article id 110983Article in journal (Refereed) Published
Abstract [en]

A comprehensive investigation is undertaken on the effect of laser scanning pattern on the microstructure of cylindrical samples made of Alloy 718 processed by Laser Powder Bed Fusion. It is observed that the common alternate direction scanning of the laser results in a more homogeneous microstructure than the less common concentric line scans where significant microstructural heterogeneities are seen between the edges and the center of the sample. The investigation focuses on the precipitation, crystallographic texture, grain size, grain morphology and residual stresses utilizing synchrotron X-ray diffraction, neutron diffraction and electron microscopy. The heterogeneous microstructure of the sample processed with the concentric laser pattern influences the chemical composition of the matrix, which alters the reference “strain free” interplanar spacing used for evaluating the residual strain. The investigation underlines the significance of the processing parameters on the homogeneity of the microstructure and the effect of the chemical variations on the determination of residual stresses in materials such as Alloy 718, where strong local chemical variations occur because of different types and extent of precipitation. © 2022

Place, publisher, year, edition, pages
Elsevier Ltd, 2022
Keywords
Laser pattern, Microstructure, Residual stress, Selective laser melting, Superalloys, Morphology, Neutron diffraction, Precipitation (chemical), Scanning, Textures, Alloy 718, Chemical variations, Cylindrical samples, Homogeneous microstructure, Laser powders, Laser scanning, Line scan, Powder bed, Residual stresses
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:ri:diva-60056 (URN)10.1016/j.matdes.2022.110983 (DOI)2-s2.0-85135381018 (Scopus ID)
Note

 Funding details: Eidgenössische Technische Hochschule Zürich, ETH; Funding text 1: JČ gratefully acknowledges financial support from the Strategic Focus Area Advanced Manufacturing (SFA-AM) initiative of the ETH Board.

Available from: 2022-09-29 Created: 2022-09-29 Last updated: 2024-04-02Bibliographically approved
Götelid, S., Ma, T., Lyphout, C., Vang, J., Stålnacke, E., Holmberg, J., . . . Strondl, A. (2021). Effect of post-processing on microstructure and mechanical properties of Alloy 718 fabricated using powder bed fusion additive manufacturing processes. Rapid prototyping journal, 27(9), 1617-1632
Open this publication in new window or tab >>Effect of post-processing on microstructure and mechanical properties of Alloy 718 fabricated using powder bed fusion additive manufacturing processes
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2021 (English)In: Rapid prototyping journal, ISSN 1355-2546, E-ISSN 1758-7670, Vol. 27, no 9, p. 1617-1632Article in journal (Refereed) Published
Abstract [en]

Purpose: This study aims to investigate additive manufacturing of nickel-based superalloy IN718 made by powder bed fusion processes: powder bed fusion laser beam (PBF-LB) and powder bed fusion electron beam (PBF-EB). Design/methodology/approach: This work has focused on the influence of building methods and post-fabrication processes on the final part properties, including microstructure, surface quality, residual stresses and mechanical properties. Findings: PBF-LB produced a much smoother surface. Blasting and shot peening (SP) reduced the roughness even more but did not affect the PBF-EB surface finish as much. As-printed PBF-EB parts have low residual stresses in all directions, whereas it was much higher for PBF-LB. However, heat treatment removed the stresses and SP created compressive stresses for samples from both PBF processes. The standard Arcam process parameter for PBF-EB for IN718 is not fully optimized, which leads to porosity and inferior mechanical properties. However, impact toughness after hot isostatic pressing was surprisingly high. Originality/value: The two processes gave different results and also responses to post-treatments, which could be of advantage or disadvantage for different applications. Suggestions for improving the properties of parts produced by each method are presented.

Place, publisher, year, edition, pages
Emerald Group Holdings Ltd., 2021
Keywords
Alloy 718, Hot isostatic pressing (HIP), Mechanical properties, Powder bed fusion electron beam (PBF-EB), Powder bed fusion laser beam (PBF-LB), Residual stress, 3D printers, Additives, Fabrication, Heat treatment, Hot isostatic pressing, Laser beams, Microstructure, Nickel alloys, Residual stresses, Shot peening, Additive manufacturing process, Building methods, Design/methodology/approach, Microstructure and mechanical properties, Nickel- based superalloys, Post-fabrication, Process parameters, Surface finishes
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:ri:diva-56709 (URN)10.1108/RPJ-12-2019-0310 (DOI)2-s2.0-85115084872 (Scopus ID)
Available from: 2021-10-04 Created: 2021-10-04 Last updated: 2024-05-21Bibliographically approved
Čapek, J., Polatidis, E., Knapek, M., Lyphout, C., Casati, N., Pederson, R. & Strobl, M. (2021). The Effect of γ″ and δ Phase Precipitation on the Mechanical Properties of Inconel 718 Manufactured by Selective Laser Melting: An In Situ Neutron Diffraction and Acoustic Emission Study. JOM: The Member Journal of TMS, 73(1), 223-232
Open this publication in new window or tab >>The Effect of γ″ and δ Phase Precipitation on the Mechanical Properties of Inconel 718 Manufactured by Selective Laser Melting: An In Situ Neutron Diffraction and Acoustic Emission Study
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2021 (English)In: JOM: The Member Journal of TMS, ISSN 1047-4838, E-ISSN 1543-1851, Vol. 73, no 1, p. 223-232Article in journal (Refereed) Published
Abstract [en]

The deformation behavior of additively manufactured Alloy 718 in as-built condition and after annealing was studied in situ under tensile loading along the build direction. Pre-characterization by synchrotron X-ray diffraction and electron microscopy revealed a significant amount of γ″ precipitates in the as-built samples, whereas the γ″ phase was entirely consumed and needle-like δ precipitates appeared in the annealed sample. In situ neutron diffraction (ND) and acoustic emission (AE) enabled indirect observation of the role of the precipitates on the mechanical behavior. ND provided information on the load accommodation in the matrix, while AE detected a strong signal from the interaction of dislocations with the δ-phase precipitates during deformation of the annealed samples. The results imply that in the annealed samples the matrix sheds the load to the precipitates, while in the as-built material the matrix bares a significant load. © 2020, The Author(s).

Place, publisher, year, edition, pages
Springer, 2021
Keywords
Annealing, Deformation, Gamma rays, Mechanical properties, Neutron diffraction, Selective laser melting, Annealed samples, Build direction, Deformation behavior, In-situ neutron diffraction, Interaction of dislocations, Mechanical behavior, Synchrotron x ray diffraction, Tensile loading, Acoustic emission testing
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-51891 (URN)10.1007/s11837-020-04463-3 (DOI)2-s2.0-85096295872 (Scopus ID)
Note

Funding details: H2020 Marie Skłodowska-Curie Actions, MSCA, 701647; Funding details: Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT, CZ.02.1.01/0.0/0.0/16_013/0001794; Funding details: Eidgenössische Technische Hochschule Zürich, ETH; Funding text 1: JČ gratefully acknowledges financial support from the Strategic Focus Area Advanced Manufacturing (SFA-AM) initiative of the ETH Board. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 701647. MK and MS gratefully acknowledge financial support from Operational Program Research, Development and Education, the Ministry of Education, Youth, and Sports, under the project “European Spallation Source—participation of the Czech Republic-OP”, Reg. No. CZ.02.1.01/0.0/0.0/16_013/0001794.

Available from: 2021-01-20 Created: 2021-01-20 Last updated: 2024-04-02Bibliographically approved
Lyphout, C., Bolelli, G., Smazalova, E., Sato, K., Yamada, J., Houdkova, S., . . . Manfredini, T. (2019). Influence of hardmetal feedstock powder on the sliding wear and impact resistance of High Velocity Air-Fuel (HVAF)sprayed coatings. Wear, 430-431, 340-354
Open this publication in new window or tab >>Influence of hardmetal feedstock powder on the sliding wear and impact resistance of High Velocity Air-Fuel (HVAF)sprayed coatings
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2019 (English)In: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 430-431, p. 340-354Article in journal (Refereed) Published
Abstract [en]

The present work aimed to clarify how the characteristics of WC-CoCr hardmetal feedstock powders, namely the grain size of the WC carbides and of the binder and the compressive strength of the sintered aggregates, affect the dry sliding wear and impact resistance of coatings deposited by High Velocity Air-Fuel (HVAF)spraying. Ball-on-Disc tests, which mimic a sliding wear process in the presence of hard asperities as it may occur e.g. in hydraulic seal joints or papermaking components, resulted in mild wear through near-surface microscale plastic flow, the exact nature of which was significantly affected by WC size. Finite element simulations of a single-asperity sliding process indeed showed that large WC grains concentrate contact stresses, thus undergoing very localised deformation. It is experimentally seen that repeated deformation of the carbide grains resulted in their cracking and pull-out. Uniformly distributed, fine carbides allowed the matrix to take on some stress, thus undergoing more homogeneous plastic flow. Block-on-Ring tests elicited adhesive wear as it may happen e.g. in metal-to-metal contacts (e.g. petrochemical valves). This could be effectively restrained by low matrix mean free path. Cyclic impact resistance of coarse-grained coatings was better than that of fine-grained ones, because of better large-scale cohesive strength.

Place, publisher, year, edition, pages
Elsevier Ltd, 2019
Keywords
Cermets, Finite element modelling, Impact wear, Sliding wear, Thermal spray coatings
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38969 (URN)10.1016/j.wear.2019.05.016 (DOI)2-s2.0-85066275915 (Scopus ID)
Available from: 2019-06-10 Created: 2019-06-10 Last updated: 2024-04-02Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-6929-3310

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