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Publications (10 of 17) Show all publications
Squillaci, L., Neikter, M., Hansson, T., Harlin, P., Niklasson, F. & Pederson, R. (2023). Extending powder particle size distribution of laser powder bed fusion Ti-6Al-4V: investigation of single tracks and multilayer experiments. In: : . Paper presented at 15th World Titanium Conference, June 2023, Edinburgh, United Kingdom.
Open this publication in new window or tab >>Extending powder particle size distribution of laser powder bed fusion Ti-6Al-4V: investigation of single tracks and multilayer experiments
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2023 (English)Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

This paper explores the effects of varying process parameters (i.e., laser power, laser scanning speed, hatch distance) on the characteristics of single tracks, triple tracks and cubes, in order to provide answers to Research Question 1. A full factorial DoE approach was adopted to produce the experiments. Data was extracted from different sources to find correlations between tracks and multilayer geometries. A digital microscope was used to obtain height profiles, whilst polished/etched cross sections cut parallel to the build direction were imaged using a LOM to obtain measurements of track height, width, melt pool depth, subsurface porosity and residual defect content in cubes. Track height was found to exceed the recoated value of 70μm for both single and triple tracks. The width of single tracks showed a clear upward trend when displayed against VED, showing a lateral expansion as energy input increased. It was also revealed that single tracks expand laterally as they grow above the substrate, indicating swelling. The melt pool depth showed a steady upward trend when plotted against LED, though less systematic than track width. A martensitic microstructure was detected, with hierarchical α’ needles growing at prescribed crystallographic directions within vertical prior-β grains. A large portion of spatter particles and unmelted powder granules were detected on the substrate and tracks, with many accumulating on the side of the tracks forming a denudation zone.

Keywords
extendign powder, laser powder
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-20988 (URN)
Conference
15th World Titanium Conference, June 2023, Edinburgh, United Kingdom
Note

This paper is under review och will be published in Proceedings.

Available from: 2023-11-24 Created: 2023-11-24 Last updated: 2024-01-08Bibliographically approved
Thalavai Pandian, K., Neikter, M., Bahbou, F., Ganvir, A., Hansson, T. & Pederson, R. (2023). Fatigue behavior of low-temperature hot isostatic pressed electron beam powder bed fusion manufactured Ti-6Al-4 V. Journal of Alloys and Compounds, 962, Article ID 171086.
Open this publication in new window or tab >>Fatigue behavior of low-temperature hot isostatic pressed electron beam powder bed fusion manufactured Ti-6Al-4 V
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2023 (English)In: Journal of Alloys and Compounds, ISSN 0925-8388, Vol. 962, article id 171086Article in journal (Refereed) Published
Abstract [en]

Ti-6Al-4 V finds application in the fan and compressor modules of gas turbine engines due to its high specific strength. Ti-6Al-4 V components manufactured using one of the additive manufacturing (AM) techniques, the electron beam powder bed fusion (PBF-EB) process, has been an active area of research in the past decade. The fatigue life of such PBF-EB built Ti-6Al-4 V components is improved by hot isostatic pressing (HIP) treatment typically performed at about 920 ˚C. The HIP treatment at 920 ˚C results in coarsening of α laths and reduced static strength and therefore a low-temperature HIP treatment is performed at about 800 ˚C to limit the impact on static mechanical properties. In the present work, the low cycle fatigue and fatigue crack growth behavior of such a modified HIP (low-temperature HIP) treated material is assessed and compared with the respective data for the standard HIP-treated material. The modified HIP-treated material has fatigue performance comparable to the standard HIP-treated material. This work suggests that the modified HIP treatment improves the static mechanical properties without significantly impacting the fatigue performance. Also, fatigue life predictions were made from the measured defect size at the crack initiation site using a linear elastic fracture mechanics tool. The life predictions show good agreement with the experimental values for defects greater than the intrinsic crack length, where life is well predicted by large-crack growth methodology. 

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Additive manufacturing Electron beam melting Hot isostatic pressing Low cycle fatigue Fatigue crack growth Ti-6Al-4 V
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-20691 (URN)10.1016/j.jallcom.2023.171086 (DOI)001031870200001 ()2-s2.0-85163861805 (Scopus ID)
Funder
Vinnova, 2019-02741
Note

CC BY 4.0

Available from: 2023-09-06 Created: 2023-09-06 Last updated: 2024-04-23Bibliographically approved
Pederson, R., Andersson, J., Joshi, S. V., Neikter, M. & Isoaho, J. (2023). Metal additive manufacturing: Motivation, process portfolio, and application potential (1ed.). In: Pederson, Robert, Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance metallic Materials: (pp. 20-40). Elsevier
Open this publication in new window or tab >>Metal additive manufacturing: Motivation, process portfolio, and application potential
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2023 (English)In: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1, p. 20-40Chapter in book (Refereed)
Abstract [en]

The idea of adding material only where needed to manufacturesolid metallic high-performing components is intriguing andone of the main reasons for the great interest in additivemanufacturing (AM) around the world. Especially whensustainability comes into play, as in recent times more thanever, AM technology is most appropriate since it enables almostfull material utilization with minimal waste. From an economicstandpoint, this becomes particularly advantageous for moreexpensive materials such as superalloys and titanium alloys.However, the route of going from a CAD drawing of a part to anadditively manufactured final component that is qualified and inserial production involves numerous challenges. The intentionof this book is to shed light on and explain some of theassociated challenges beginning with the importance of thestarting material and how it is manufactured, i.e., wire orpowder, continuing into description of the conventional andPederson, R., Andersson, J., & Joshi, S. (2023). Additive manufacturing of high-performance metallic materials. Elsevier.Created from vast-ebooks on 2024-01-08 16:09:20. Copyright © 2023. Elsevier. All rights reserved.most commonly used AM processes, followed by postbuildtreatments and nondestructive evaluations, to eventuallyproduce the final part with mechanical performance consistentwith the application requirements. In the end, selected realindustry examples of AM parts for actual applications will bepresented

Place, publisher, year, edition, pages
Elsevier, 2023 Edition: 1
Keywords
Additive manufacturing; Superalloys; Titanium alloys; Powder; Wire; Postbuild treatment; Nondestructive evaluation; Mechanical properties
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21065 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-26Bibliographically approved
Karimi Neghlani, P., Thalavai Pandian, K. & Neikter, M. (2023). Processing of high-performance materials by electron beam-powder bed fusion (1.ed.). In: Pederson, Robert,Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance Metallic Materials: (pp. 103-181). Elsevier
Open this publication in new window or tab >>Processing of high-performance materials by electron beam-powder bed fusion
2023 (English)In: Additive Manufacturing of High-Performance Metallic Materials / [ed] Pederson, Robert,Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., p. 103-181Chapter in book (Refereed)
Abstract [en]

Electron beam-powder bed fusion (EB-PBF) is a process that uses a highly intense electron beam to melt metallic powders to create parts. In comparison to a conventional process, EB-PBF is more efficient at producing customized and specific parts in industries such as aerospace, space, and medical. Additionally, the EB-PBF process is used to manufacture highly complex parts for which other technologies would be prohibitively expensive or difficult to apply; increased geometric complexity does not necessarily imply increased cost. However, because the interaction of the electron beam with the powder and substrate material is complex, a high level of knowledge is required to master the skill of producing structurally sound components. This chapter discusses crucial features of the process parametermicrostructure-defect relationship that must be taken into Electron beam-powder bed fusion (EB-PBF) is a process that uses a highly intense electron beam to melt metallic powders to create parts. In comparison to a conventional process, EB-PBF is more efficient at producing customized and specific parts in industries such as aerospace, space, and medical. Additionally, the EB-PBF process is used to manufacture highly complex parts for which other technologies would be prohibitively expensive or difficult to apply; increased geometric complexity does not necessarily imply increased cost. However, because the interaction of the electron beam with the powder and substrate material is complex, a high level of knowledge is required to master the skill of producing structurally sound components. This chapter discusses crucial features of the process parametermicrostructure-defect relationship that must be taken into account in order to generate sufficiently sound builds of highperformance materials employing EB-PBF.

Place, publisher, year, edition, pages
Elsevier, 2023 Edition: 1.
Keywords
Electron beam-Powder bed fusion; Process parameters; Microstructure; Defects
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21067 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-11Bibliographically approved
Mahade, S., Bhattacharya, P., Tolvanen, S., Pederson, R. & Neikter, M. (2023). Processing of high-performance materials by laser directed energy deposition with wire (1.ed.). In: Pederson, Robert, Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance metallic Materials: (pp. 260-305). Elsevier
Open this publication in new window or tab >>Processing of high-performance materials by laser directed energy deposition with wire
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2023 (English)In: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., p. 260-305Chapter in book (Refereed)
Abstract [en]

Processing of metallic materials by Laser Directed Energy Deposition (LDED), with Wire (w) as the feedstock, enables the manufacturing of high precision, near-net shape components that require minimal postmachining, without compromising the performance. L-DEDw has also shown the capability to add intricate features on large structures, which makes it an attractive fabrication technique for aerospace application. The key merits of wire as the feedstock when compared to powder include; higher deposition rates, low porosity in the deposited material, excellent surface finish, and, ∼ 100% utilization of the feedstock. However, despite the attractive merits, the difference in solidification rates during L-DEDw processing when compared to other fabrication routes could induce high residual stresses, which can be detrimental to the integrity of cracksensitive alloys. Additionally, there exists an inherent challenge during L-DEDw fabrication, where controlling the process variables to ensure stable deposition conditions becomes essential to achieve repeatable, and desired results. The recent advancements in the area of monitoring and control systems, and their integration with L-DEDw processing, have enabled to overcome the processing instability related challenges. Furthermore, different L-DEDw processing strategies for alleviating residual stresses (tensile) accumulation in the deposits are discussed, which could enable defectfree, high-performance component fabrication. Although the utilization of L-DEDw for processing diverse alloy systems has been explored in the literature, the current chapter's scope is restricted to L-DEDw processing of Nickel-based and Titanium-based alloys, which are often utilized in the aeroengine. This work aims to provide a holistic perspective and shed light on the state-of-the-art, recent developments, sustainability aspects and future directions for L-DEDw processed, highperformance Ni-based and Ti-based alloys.

Place, publisher, year, edition, pages
Elsevier, 2023 Edition: 1.
Keywords
Laser directed energy deposition with wire; Process parameters; Microstructure; Residual stress; Nibased superalloys; Ti-based alloys; Hot cracking; Lack of fusion
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21072 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-12Bibliographically approved
Segerstark, A. & Neikter, M. (2023). Processing of high-performance materials by laser-directed energy deposition with powders (1.ed.). In: Pederson, Robert, Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance metallic Materials: (pp. 230-259). Elsevier
Open this publication in new window or tab >>Processing of high-performance materials by laser-directed energy deposition with powders
2023 (English)In: Additive Manufacturing of High-Performance metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., p. 230-259Chapter in book (Refereed)
Abstract [en]

Processing of high-performance materials by Directed Energy Deposition with Powders (L-DED-P) is frequently utilized in repair as well as remanufacturing apart from manufacturing. One benefit of the process is the low heat input in comparison to, i.e., L-DED with wire which is preferable regarding residual stresses and distortion. However, care must be taken to minimize defects that are at stake in forming if process parameters are not adequately adapted to the specific application. There is a strong correlation between the process parameters and metallurgical behavior which in turn give rise to potential defects and the final performance of the part to be produced. This chapter gives an overview of the processmicrostructure-defect relations that are of importance in L- DED-P processing.

Place, publisher, year, edition, pages
Elsevier, 2023 Edition: 1.
Keywords
Laser-directed energy deposition with powders; Process parameters; Powder; Microstructure; Porosity; Lack-of-fusion; Hot cracking
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21071 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-12Bibliographically approved
Raza, T., Adegoke, O., Squillaci, L. & Neikter, M. (2023). Processing of high-performancematerials by laser beam-powderbed fusion (1.ed.). In: Pederson, Robert, Andersson, Joel & Joshi, Shrikant V. (Ed.), Additive Manufacturing of High-Performance Metallic Materials: (pp. 182-229). Elsevier
Open this publication in new window or tab >>Processing of high-performancematerials by laser beam-powderbed fusion
2023 (English)In: Additive Manufacturing of High-Performance Metallic Materials / [ed] Pederson, Robert, Andersson, Joel & Joshi, Shrikant V., Elsevier, 2023, 1., p. 182-229Chapter in book (Refereed)
Abstract [en]

Processing of high-performance materials by laser beam powder bed fusion (LB-PBF) provides an alternative manufacturing route to, i.e., investment casting and is suitable for production of high-performance materials having complex geometry such as turbine blades. The main benefit of powder bed fusion in general is associated with the fact that increased geometrical complexity does not add any cost. However, the processability of the alloys of interest is closely linked to process parameters where highperformance materials belong to a special class of materials that need substantial attention to avoid problems, not at least with regard to different types of cracking. In this chapter, the relationship between process parameter-microstructure-defect relationship will be discussed and analyzed.

Place, publisher, year, edition, pages
Elsevier, 2023 Edition: 1.
Keywords
Laser beam powder bed fusion; Process parameter; Microstructure; Defect; Cracking
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-21070 (URN)9780323918855 (ISBN)9780323913829 (ISBN)
Available from: 2023-12-14 Created: 2023-12-14 Last updated: 2024-01-12Bibliographically approved
Edin, E., Svahn, F., Neikter, M. & Åkerfeldt, P. (2023). Stress relief heat treatment and mechanical properties of laser powder bed fusion built 21-6-9 stainless steel. Materials Science & Engineering: A, 868, Article ID 144742.
Open this publication in new window or tab >>Stress relief heat treatment and mechanical properties of laser powder bed fusion built 21-6-9 stainless steel
2023 (English)In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 868, article id 144742Article in journal (Refereed) Published
Abstract [en]

In this work, the effectiveness of residual stress relief annealing on a laser powder bed fusion (L-PBF) manufactured austenitic stainless steel, alloy 21-6-9 was investigated. Residual stress levels were gauged using geometrical distortion and relaxation testing results. In the investigated temperature interval (600–850 °C), shape stability was reached after subjecting the as-built material to an annealing temperature of 850 °C for 1 h. Microstructural characterization and tensile testing were also performed for each annealing temperature to evaluate the alloy’s thermal stability and the resulting tensile properties. In the as-built state, a yield strength (YS) of 640 MPa, ultimate tensile strength (UTS) of 810 MPa and 4D elongation of 47% were measured. Annealing at 850 °C for 1 h had little measurable effect on ductility (48% 4D elongation) while still having a softening effect (UTS = 775 MPa, YS = 540 MPa). From the microstructural characterization, cell-like features were observed sporadically in the annealed condition and appeared stable up until 800 °C after which gradual dissolution began, with the last remnants disappearing after subjecting the material to 900 °C for 1 h. © 2023 The Authors

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Annealing; Residual stresses; Steel testing; Stress relief; Tensile strength; Annealing temperatures; Laser powder bed fusion; Laser powders; Microstructural characterizations; Powder bed; Relaxation testing; Stainless steel alloys; Stress levels; Stress relief annealing; Ultimate tensile strength; Tensile testing
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-19822 (URN)10.1016/j.msea.2023.144742 (DOI)001018900200001 ()2-s2.0-85148068227 (Scopus ID)
Note

CC-BY-NC-ND 4.0 

Acknowledgement for financial contributions from the RIT project (Space for Innovation and Growth), The Swedish National Space Agency (research program NRFP) and GKN Aerospace Sweden AB. The stress relaxation testing was funded by Västra Götalandsregionen, Tillväxtverket, European Regional Development Fund, and the Spacelab project (Grant number 20201639). 

Available from: 2023-11-03 Created: 2023-11-03 Last updated: 2024-01-15Bibliographically approved
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) Epub ahead of print
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.

Keywords
Austenitic stainless steel, Process parameters, Laser powder bed fusion (PBF-LB), JBK-75, Design of experiment (DOE), Tensile properties
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-20015 (URN)10.1016/j.msea.2023.144911 (DOI)001029577000001 ()2-s2.0-85153940822 (Scopus ID)
Funder
Region Västra Götaland, 20201639Swedish Agency for Economic and Regional Growth, 20201639
Note

Västra Götalandsregionen through Tillväxtverket (European Regional Development Fund) and GKN Aerospace Sweden AB funded this research project through the Spacelab project (grant number 20201639). 

Available from: 2023-06-02 Created: 2023-06-02 Last updated: 2024-01-15Bibliographically approved
Andersson, J., Hosseini, V., Neikter, M. & Pederson, R. (2023). Welding of special alloys. In: Fuad Khoshnaw (Ed.), Welding of Metallic Materials: Methods, Metallurgy, and Performance (pp. 279-316). Elsevier
Open this publication in new window or tab >>Welding of special alloys
2023 (English)In: Welding of Metallic Materials: Methods, Metallurgy, and Performance / [ed] Fuad Khoshnaw, Elsevier , 2023, p. 279-316Chapter in book (Other academic)
Abstract [en]

Specialty alloys are a broad group of materials providing superior properties to common materials and are therefore used for more demanding applications. Specialty alloys require sophisticated manufacturing routes, e.g., vacuum metallurgy, to account for all the alloying elements needed to finalize the specific alloy for its intended purpose. The alloys of Duplex stainless steels, superalloys, and Titanium alloys are examples of so-called specialty alloys where aerospace, chemical, and petrochemical industries are just a few areas mentioned where these specialty alloys are frequently used. Duplex stainless steel, had superior mechanical properties and corrosion resistance, making them a sustainable choice for a wide variety of applications i.e., petrochemical industries. The superalloys, and especially the precipitation hardening ones belong to a unique plethora of alloys commonly used in aerospace as well as land-based gas turbines which possess superb mechanical performance at elevated temperatures. However, the superalloys are unfortunately very challenging to process, not at least regarding weld cracking. With their high specific strength and corrosion resistance, titanium alloys are favorable for numerous applications. However, they react readily with oxygen at elevated temperatures and therefore inert atmosphere must be used during welding. 

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Specialty alloys, welding, super alloy, special alloys
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-19832 (URN)10.1016/B978-0-323-90552-7.00003-1 (DOI)2-s2.0-85150109624 (Scopus ID)9780323906708 (ISBN)9780323905527 (ISBN)
Available from: 2023-11-07 Created: 2023-11-07 Last updated: 2024-01-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3772-4371

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